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new cam selection - your opinion

Started by Stegs, September 14, 2015, 07:58:57 AM

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Stegs

Looking for a new cam, something very streetable with good cruising manors, but i want the idle to have a nice bump to it

Im looking at hughes whiplash cam with lifters and springs

now ive been watching youtube to find what sound im after, and i found a nice video on a 292 cam.


Wondering if you guys can give me some insight as far as cams in the "292"

Ive searched and came up with comp cams, mopar purple cam, lunati voodoo i think


anyway, your input is appreciated. Wondering what you guys suggest, what you have, what works, what dont etc....


this is for a 440, 906 head, stock manifolds

Challenger340

HUH ?
FORGET IT !
"Very streetable with good cruising manors" is just NOT to be used in the same sentence when contemplating ANYTHING in the "292" Camshaft range,
and, IMO...
anybody recommending Cams in the "292" range for your 440 application, little-lown at sub 9's to one Compression Ratio, are on fawking GLUE !

But nonetheless,
Intake valve closing points(again lsa related) between 70* to 72* are common on Cams in the "292" range, you just won't find any 292 Cams that are shorter.

When it comes to selecting a Camshaft.... I would implore you to research and Educate yourself FIRST ! for best results.
and a good tool for doing so utilizing the info I have provided above can be found here:
http://www.wallaceracing.com/dynamic-cr.php

Use the above calculator.
Plug in your engine data, with any 292 Cam closing point, and you can easily see that even a true "9.5:1" C.R. Engine(which your 906 headed 440 is NOT)
very quickly...
becomes a 6.5:1 Compression Ratio Engine.
Which might "sound" really cool at idle, but will be an absolute DAWG below 3,500 rpm


 
Only wimps wear Bowties !

Stegs

Quote from: Challenger340 on September 14, 2015, 11:46:39 AM
HUH ?
FORGET IT !
"Very streetable with good cruising manors" is just NOT to be used in the same sentence when contemplating ANYTHING in the "292" Camshaft range,
and, IMO...
anybody recommending Cams in the "292" range for your 440 application, little-lown at sub 9's to one Compression Ratio, are on fawking GLUE !

But nonetheless,
Intake valve closing points(again lsa related) between 70* to 72* are common on Cams in the "292" range, you just won't find any 292 Cams that are shorter.

When it comes to selecting a Camshaft.... I would implore you to research and Educate yourself FIRST ! for best results.
and a good tool for doing so utilizing the info I have provided above can be found here:
http://www.wallaceracing.com/dynamic-cr.php

Use the above calculator.
Plug in your engine data, with any 292 Cam closing point, and you can easily see that even a true "9.5:1" C.R. Engine(which your 906 headed 440 is NOT)
very quickly...
becomes a 6.5:1 Compression Ratio Engine.
Which might "sound" really cool at idle, but will be an absolute DAWG below 3,500 rpm


 

good info

but the hughes cam, right on their website says its perfect for 9.5 compression motors or less

that is a better cam than any 292?

Challenger340

Right away you are NOT comparing "apples to apples" because that Hughes is NOT anywhere near "292" ! more like a 255 to 265 ? seat to seat..... albeit  on a very fast ramp so as to maintain cylinder pressure !

You never GAIN anything... without giving something UP !
That's why the educational process is SO IMPORTANT ! to understand fully what you may be "gaining", as opposed to what you could be LOSING ?
The Hughes whiplash is a 229* @ .050" Intake Lobe profile closing at 36* ABDC @ .050", ground on a true .904" lifter Diameter ramp speed requiring 150# V/Spring Seat pressures and 330# over the nose at .518" Lift....
which is problematic all by itself long term on the street without killing Lobes with well over over 300 lb pressures on a Flat Tappet Cam, little-lown trying to break the Cam in properly or run it on stamped steel Rockers ?, which IMO forget it if you are even thinking about the whiplash, and default to Adjustable Rockers and Cup & Ball type pushrods at the very least.

So bottom line here....
yes, the whiplash would work with the low compression and it would sound cool with probably best power in the 268 to 274 Cam Size ranges.
However,
it will be difficult to break-in with the recommended V/Spring pressures(even with lots of zinc), and you would be highly advised to get stronger adjustable Rocker Arms and Pushrods(ditch the stock stamped steel). I would also add, that even if you do get it broken in properly, don't let the Engine Idle when hot more than it has to once driving it for best longevity.

The trade off is best power versus tough break in and longevity.
Only wimps wear Bowties !

c00nhunterjoe

In my opinion, to get "a little thump" yet maintain some bottom end drivability, you need to go solid, not hydraulic. Follow everything else that was just suggested. The aggressive ramps make power but take away lots of life. Something along the lines of the comp xs268 or 274 will give you the thumping idle but still have decent midrange and bottom end. As you go more aggressive with the stock grinds, you will lose bottom end power. If you plan on keeping the exhaust manifolds, i suggest talking to bsb67 about custom cam grinds.

69wannabe

A good out of the box hydraulic street cam is a XE268 comp cam. Got a friend that has this cam in his 440 and it sound's good with flowmaster 3 chamber mufflers and it has factory 906 heads but he is running headman headers and the rest of his valve train is stock except for the matching valve spring's and new retainers and lock's. It is a 75 model 440 but he does have the 2355 speed pro forged piston's but even if you do not have these exact pistons this cam should work with a slightly lower compression ratio anyway and have good low to mid range power and street manners. This is pretty much as big as you can go without a stall converter in my opinion. Also watch your cam choice's lift with a stock head, from my understanding on a stock 906 head you can only go up to a 509 lift without machining the valve guides down to keep the valve spring retainers from bottoming on the top of the valve guide. I am not 100% sure about this but I have read or heard someone say this sometime or other. I am pretty sure the lift on the XE268 is 477 intake and 481 exhaust which is a decent lift and does not put your valve train in a giant strain.
Lot's of cams out there and lot's of mistakes to be made too. If you are going to upgrade your cam you can also upgrade to some good long tube headers and you will notice a pretty good jump in performance!!!!  Check out mopar muscle website and search for 440 resto to rad and it will give you some ideas to what you can expect from performance add on's!!!

Stegs

Quote from: 69wannabe on September 14, 2015, 09:29:24 PM
A good out of the box hydraulic street cam is a XE268 comp cam. Got a friend that has this cam in his 440 and it sound's good with flowmaster 3 chamber mufflers and it has factory 906 heads but he is running headman headers and the rest of his valve train is stock except for the matching valve spring's and new retainers and lock's. It is a 75 model 440 but he does have the 2355 speed pro forged piston's but even if you do not have these exact pistons this cam should work with a slightly lower compression ratio anyway and have good low to mid range power and street manners. This is pretty much as big as you can go without a stall converter in my opinion. Also watch your cam choice's lift with a stock head, from my understanding on a stock 906 head you can only go up to a 509 lift without machining the valve guides down to keep the valve spring retainers from bottoming on the top of the valve guide. I am not 100% sure about this but I have read or heard someone say this sometime or other. I am pretty sure the lift on the XE268 is 477 intake and 481 exhaust which is a decent lift and does not put your valve train in a giant strain.
Lot's of cams out there and lot's of mistakes to be made too. If you are going to upgrade your cam you can also upgrade to some good long tube headers and you will notice a pretty good jump in performance!!!!  Check out mopar muscle website and search for 440 resto to rad and it will give you some ideas to what you can expect from performance add on's!!!

comp cams xe268 is what i will go with, has the exact sound im looking for and it will work

I was told with the hughes i need new springs and lifters with the cam.....is the same true for this comp xe268?


Sorry guys, im very new to engines and building them. IM a jeep guy, all we do is add better gears to help with the lift and rims/tires

I never did internal stuff, always bolt ons. IM learning, gaining little by little info as i go

Please let me know what i would need to order for the comp cams.....as i will get it ordered as soon as i sell a few guns!

edit, would the xe275 work in my motor?

https://www.youtube.com/watch?v=iLmD6KJhb9Y


https://www.youtube.com/watch?v=DbaR0CuWG4g

I love this sound....but would it work or be a dog? i want to wake up the motor a little bit with a new cam and a holley 750


Challenger340

You do not have sufficient cylinder pressure available(Compression ratio) for best results with any Cam larger than the xe268..... and even it should be considered a MAXIMUM,
and,
even with just the xe268 you will lose noticeable "off the line" power without a torque convertor or gear change, but once it gets the rpm up it will be OK.

A Camshafts advertised rpm "range" is based on the Engines Compression Ratio satisfying the Camshaft's requirement.
For example:
a Cam "advertised" as having a 2,500 to 6,000 rpm powerband, might assume or "ask" for 9.0:1 at sea level.
Now,
put that Cam in an 8.5:1 C.R. Engine at 2,500 ft elevation.... and it will probably be a dawg below 3,000 rpm ?

The above is why... when looking at Cam Swaps, it is better to select a Cam SMALLER than what you think based on C.R., or always UNDER-cam slightly if in doubt of actual C.R.  

IMO, selecting a Camshaft based on the "sound" it makes, is a recipe for disaster.
especially if lower compression ratios are probably.

Only wimps wear Bowties !

firefighter3931

For a low compression build with restrictive manifold exhaust the best choice is a cam profile with a wide 112* LSA and short duration with a split pattern.  :2thumbs:

The cam I would chose is the Lunati VooDoo  #10230702

-262/268 advertised
-220/226 @.050
-112 LSA
-.475/.494 lift @ 1.5



Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

Challenger340

Quote from: firefighter3931 on September 15, 2015, 01:10:48 PM
For a low compression build with restrictive manifold exhaust the best choice is a cam profile with a wide 112* LSA and short duration with a split pattern.  :2thumbs:

The cam I would chose is the Lunati VooDoo  #10230702

-262/268 advertised
-220/226 @.050
-112 LSA
-.475/.494 lift @ 1.5



Ron

This is EXTREMELY good advice in a Camshaft !  :2thumbs:

PAY ATTENTION !






Only wimps wear Bowties !

BSB67

Wow Bob, you're on fire.   ;D

Stegs - Refresh my memory, you have the motor that your machinist says is 9.5:1 but could not get to us the piston part number?  Did you ever get a cylinder pressure test?  You should do that.

Ron's cam recommendation is probably a good match, but going the opposite direction for the sound you are looking for.  The 268/274 would probably be okay too.  The cylinder pressure information would help in the decision.  The larger cam would give you more lope at idle.

If you want to go off the reservation from everything recommended so far, I would suggest the smallest Comp Cam Thumpr. It will give you the idle you want, it has lolly pop ramps that will be easy on parts, and won't hurt your cylinder pressure too much more.  Might be able to keep most or all of your valve train.

If it is about the sound, probably your best pick for something off the shelf.

Bottom line is the cam sets the overall characteristics of the car, and only you can say what is best for you.  Cam swaps are easy.  Once you do one, they're really easy.  We use to do cam swaps on Saturday mornings.  Today we seem to spend more time analyzing what the perfect cam might be verses the time required to actually install a couple.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

69wannabe

Quote from: firefighter3931 on September 15, 2015, 01:10:48 PM
For a low compression build with restrictive manifold exhaust the best choice is a cam profile with a wide 112* LSA and short duration with a split pattern.  :2thumbs:

The cam I would chose is the Lunati VooDoo  #10230702

-262/268 advertised
-220/226 @.050
-112 LSA
-.475/.494 lift @ 1.5





Ron





This is very good advise!!!! This cam is just a touch smaller in duration than the XE268 and will still have a good sound and will keep your lower RPM power too!!! You will need to purchase all matched item's for a cam swap tho... Cam,lifters, springs and retainers and lock's that are recommended for that cam.  The XE275 would be a bad choice unless you want to make alot of costly changes. The XE274 is what I ran in my 440 and I really liked it alot but the engine was matched to that cam and I have a 4-speed so I didn't have to worry about a stall converter. I based my build similar to the mopar muscle resto to rad rebuild and the XE274 was their favorite choice for a cam at the time and it did run good for me.

Stegs

thanks guys

I looked for the paper work last night for the engine build, i couldnt find it, but i may have put it in the safe by the build sheet


The cam i have now works, if buying a new cam isnt going to give me the sound i want (and work good with my motor)

Ill probably just end up keeping what i have then, and spending the money elsewhere on the car. As this one works fine, just doesnt have the sound.


I wanted a new cam for better sound, if the lunati cam is not much for lumpy idle (which is what i have now) i dont see a reason to replace it, just to get the same results




I will dig up the papers, make a phone call to the engine builder and get the part numbers that he used.

Scaregrabber

Never buy a cam for the sound. If what's in there works well just leave it in.
My son has the above mentioned Lunati in his truck 440 and it works like gangbusters, however my friend also has that Whiplash camshaft in the low compression 440 in his 71 Charger and it pulls way better than it should too. They are both good cams from what I have seen. Seat pressure is a bit high with the Whiplash but it started immediately, broke in correctly and it runs hard, not a bad thing to say about it.
As far as Comp cam's 268, no thanks. I know of 3 locals that have had problems with them in BBD's, maybe coincidence but maybe not, they all ate lobes.

Sheldon

BSB67

Quote from: Scaregrabber on September 17, 2015, 12:16:57 AM
.....however my friend also has that Whiplash camshaft in the low compression 440 in his 71 Charger and it pulls way better than it should too. They are both good cams from what I have seen. Seat pressure is a bit high with the Whiplash but it started immediately, broke in correctly and it runs hard, not a bad thing to say about it.


I've gotten the same feedback from a few folks using the Whiplash and Thumpr cams.  The Thumpr is softer version of the Whiplash.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

Stegs

Quote from: Scaregrabber on September 17, 2015, 12:16:57 AM
Never buy a cam for the sound. If what's in there works well just leave it in.
My son has the above mentioned Lunati in his truck 440 and it works like gangbusters, however my friend also has that Whiplash camshaft in the low compression 440 in his 71 Charger and it pulls way better than it should too. They are both good cams from what I have seen. Seat pressure is a bit high with the Whiplash but it started immediately, broke in correctly and it runs hard, not a bad thing to say about it.
As far as Comp cam's 268, no thanks. I know of 3 locals that have had problems with them in BBD's, maybe coincidence but maybe not, they all ate lobes.

Sheldon

well reading about the whiplash cam from hughes, that is designed for low compression motors, it even says 9.2 is on the high side. So if im at 8.5 or 9.0 compression in my motor, that cam should work

I planned on getting new springs and lifters as suggested by them. As far as break in, id have the guy who built my motor do the swap since he knows how to do it right and has the tools to do it


Ive been talking to a guy on youtube via email about his cuda. He has a 340, 8:5 compression, maybe 9.0 (he says its real basic, so more than likely 8:5)

any way its a 340, stock heads, not ported at all. he has a performer rpm intake and a 750 holley. He told me everything works well, and he loves the cam. He said it really made his stock 340 come alive (for being a lower compression motor)

here is a link to his youtube page, im sure most of you have seen it

https://www.youtube.com/watch?v=3aiKrwGXFOo

these are the videos that made me look into whiplash cams for my lower compression motor

Challenger340

Quote from: Stegs on September 17, 2015, 06:33:48 AM
Quote from: Scaregrabber on September 17, 2015, 12:16:57 AM
Never buy a cam for the sound. If what's in there works well just leave it in.
My son has the above mentioned Lunati in his truck 440 and it works like gangbusters, however my friend also has that Whiplash camshaft in the low compression 440 in his 71 Charger and it pulls way better than it should too. They are both good cams from what I have seen. Seat pressure is a bit high with the Whiplash but it started immediately, broke in correctly and it runs hard, not a bad thing to say about it.

As far as Comp cam's 268, no thanks. I know of 3 locals that have had problems with them in BBD's, maybe coincidence but maybe not, they all ate lobes.
This would seem to suggest some kind of poor quality or "flaw" in the Camshaft ? To each their own, and it is any consumer's perogative to purchase according to reputations they percieve.
That said,
I have run-in literally hundreds of CompCams as an engine builder, and NEVER had a failure ?


Sheldon

well reading about the whiplash cam from hughes, that is designed for low compression motors, it even says 9.2 is on the high side. So if im at 8.5 or 9.0 compression in my motor, that cam should work
As long as you, or ANYBODY ELSE reading this.... are cognizant going into this Stegs, that there is indeed no "magic" involved in this Camshaft. It is nothing "new" !
And I am NOT knocking Hughes Cams.... just stating the "considerations" here.
As with everything, including Camshafts, you do not "gain" anything.....without "giving something up". Which in the case of the whiplash is to shut the Intake Valve as close as possible after BDC, to trap as much compression as possible in a low compression engine.... AND..... still provide as much duration @ .050" and Valve Lift for performance. This is accomplished by running fast Cam Lobes ramp rates, WHICH... require increased Valve Spring pressure to "keep up" with faster .904" lobes.
The GAIN twofold:  trapping much needed "compression" in low compression engines, with added duration @ .050(flow) for power.
The trade offs to get the above: the increased Valve Spring Pressures and Rates required, to "keep up" with the faster lobes, which can be more difficult to patent break-in, and harder on stock parts(rockers, etc.)
I would humbly suggest EDM style Lifters to aassist with break-in, but adds to the expense considerable vrs stock lifters


I planned on getting new springs and lifters as suggested by them. As far as break in, id have the guy who built my motor do the swap since he knows how to do it right and has the tools to do it
Is this the same gentleman that can NOT remember what Piston was used in your engine ? and was claiming 9.5:1 with no build sheet ?  CC data ? or Piston number ?
IMO, You may wish to re-think the definition of "he knows how to do it right" ?
Nonetheless, maybe ask him SPECIFICALLY, to actually DEGREE THE CAMSHAFT when he installs it ? (If it's NOT too much trouble)



Ive been talking to a guy on youtube via email about his cuda. He has a 340, 8:5 compression, maybe 9.0 (he says its real basic, so more than likely 8:5)

any way its a 340, stock heads, not ported at all. he has a performer rpm intake and a 750 holley. He told me everything works well, and he loves the cam. He said it really made his stock 340 come alive (for being a lower compression motor)

here is a link to his youtube page, im sure most of you have seen it

https://www.youtube.com/watch?v=3aiKrwGXFOo

these are the videos that made me look into whiplash cams for my lower compression motor
I would be curious to know the stall speed of the convertor used as well as the rear gearing ?
nonetheless,
when I watched the video link a few things were "remarkable" and caught my eye ?
1.) THAT, is the first 340 I have ever seen "chirp" the tires with an automatic shifting into 3rd "drive" ? AND MUCH BE ONE HELL OF A SHIFT KIT ! 00.21 second mark.
2.) have a good look and compare the tire "Bulge"in the fronts compared to the "rears" at the 00.29 second mark ? ZERO BULGE IN THE REARS !
3.) I can't see any "black" marks on the pavement anywhere in the video that he is leaving ?
WHICH IMO, LEADS ME TO BELIEVE THE GUY HAS 50 PSI IN THE REAR TIRES ?


Good Luck in your Engine "tweek" Stegs, I sincerely hope things work out well.
Only wimps wear Bowties !

firefighter3931

Scott,

Are you planning to install a set of long tube headers with the cam swap ?

The Thumper/Whiplash cams are ground on a tight 107* LSA which will not work well with a restrictive (manifold) exhaust. You need headers to make either of those cams work properly:yesnod:

The increased valve overlap will decrease idle vacuum and make tuning more difficult. If the car has a power brake booster you will need to add an electric pump to the brakes....or switch to a manual brake master cylinder.  :P

There are lots of things to consider when making a cam swap and the least significant on that list is the lope at idle...inmho  ;)

It would be nice to know what cam is in there now and what pistons were used in the engine build.  :scope:

Be very careful with cam selection....one wrong move and you'll turn a descent running car into a pooch that won't idle, can't run power brakes and won't turn a tire over to save it's life.  :eek2:


Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

cdr

Stegs, pay attention to what firefighter [Ron] & challenger340 [Bob] are TRYING to tell you !!!!
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

Stegs

just sent ron my engine specs.

piston numbers, head resurface amount

cam specs

hopefully everything he needs.

Im waiting to hear back the good or bad news.... :scratchchin:

Challenger340

Quote from: Stegs on September 17, 2015, 03:22:18 PM
just sent ron my engine specs.

piston numbers, head resurface amount

cam specs

hopefully everything he needs.

Im waiting to hear back the good or bad news.... :scratchchin:

Good job Stegs, now you are doing things right  :2thumbs:
Only wimps wear Bowties !

Stegs

Quote from: Challenger340 on September 17, 2015, 04:37:38 PM
Quote from: Stegs on September 17, 2015, 03:22:18 PM
just sent ron my engine specs.

piston numbers, head resurface amount

cam specs

hopefully everything he needs.

Im waiting to hear back the good or bad news.... :scratchchin:

Good job Stegs, now you are doing things right  :2thumbs:


It took me a while to find the info. I had in my safe by my build sheet...it was among all the receipts for the car  ;)




BSB67

Quote from: Stegs on September 18, 2015, 11:04:22 AM
Quote from: Challenger340 on September 17, 2015, 04:37:38 PM
Quote from: Stegs on September 17, 2015, 03:22:18 PM
just sent ron my engine specs.

piston numbers, head resurface amount

cam specs

hopefully everything he needs.

Im waiting to hear back the good or bad news.... :scratchchin:

Good job Stegs, now you are doing things right  :2thumbs:


It took me a while to find the info. I had in my safe by my build sheet...it was among all the receipts for the car  ;)


So, what the part number, 1263, or 1276?

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

Stegs

1263

i fell kinda screwed on my engine build

I was very clear to him, that i wanted my motor to be 9.5 compression

These pistons he said would be that ratio, as far as what his book said, but it didnt say what heads it was matched with and it obviously isnt 906 iron heads


Does anybody know what heads they would use to rate those pistons at 9.5? He said there were 2 types , a taller piston and a shorter, I got the taller

anyway, long long story short, Ron suggest a proform carb to give the motor more air , as that should help it more


I must say for what my motor is, it does move pretty good. Im not disappointed in it, its just not what what i thought i paid for

maybe start saving for a stroker kit from 440 source, they seem to be "all in 1 kit" minus the heads


for the time being, just continue to enjoy the car as the season is winding down here in michigan. Start ordering parts over the fall and winter so its ready to go again in the spring


Challenger340

Quote from: Stegs on September 20, 2015, 07:46:42 PM
1263

i fell kinda screwed on my engine build

I was very clear to him, that i wanted my motor to be 9.5 compression

These pistons he said would be that ratio, as far as what his book said, but it didnt say what heads it was matched with and it obviously isnt 906 iron heads


Does anybody know what heads they would use to rate those pistons at 9.5? He said there were 2 types , a taller piston and a shorter, I got the taller

anyway, long long story short, Ron suggest a proform carb to give the motor more air , as that should help it more


I must say for what my motor is, it does move pretty good. Im not disappointed in it, its just not what what i thought i paid for

maybe start saving for a stroker kit from 440 source, they seem to be "all in 1 kit" minus the heads


for the time being, just continue to enjoy the car as the season is winding down here in michigan. Start ordering parts over the fall and winter so its ready to go again in the spring



Does anybody know what heads they would use to rate those pistons at 9.5?
It's really simple... THERE IS NO FACTORY IRON HEAD THAT WOULD PROVIDE 9.5:1 WITH THOSE PISTONS.... NEVER WAS.... AND ALL THERE EVER WAS(IMO anyways) WAS A "THEORETICAL" MINIMUM CC FROM A SANCTIONING BODY BACK IN THE 1970'S !
But nobody knows for sure, just from the information I could garner.

Let me explain.
Silv-O-lite's provided counter data in the catalogs list between 8.8 to 9.5:1 for the "HIGH" #1263 Piston, and has forever.
Which,
on an UN-milled .030" overbore 440 Block, using any normal .039" thick composition style Head Gasket,
* would require a Cylinder Head around 71 CC's for the 9.5:1 C.R.
and
* require around an 80 CC Cylinder Head for the 8.8:1 C.R.

There are only 2 styles of factory BB Mopar cast iron cylinder heads, which in the REAL WORLD measure for CC's as follows
One is a closed Chamber design, most of which(#2406516 and # 2780915) CC "as cast" after rebuild around 78 to 80 CC mark
and
Two, the open Chamber designs(452, 906, etc., etc) which most "as cast" after rebuilding CC in the 87 CC to as high as 90 CC range.

After numerous phonecalls and emails I have had over the years with Silv-o-lite regarding these pistons(the #1276 and #1263), and pointing out repeatedly to them, that their C.R. numbers were WAY OFF ? based on numbers I provided them, etc., etc., and asking them point blank what numbers/data THEY were using in their calcs ?
The best info I can relate from my correspondence with them is this:
1.) Those pistons were designed way back in the late 1970's ?
2.) The cylinder head CC data they were using at that time, was the published N.H.R.A. "minimum" specs in those days, for the closed and open chamber BB mopar heads being 73.5 CC and 79.5 CC's respectively.(nobody bothered to notice than those were minimums that the heads could be MILLED down to , so as to stay legal at an N.H.R.A. event, rather than "real world" sizes)
3.) Silv-o-lite has been well aware of the problem in C.R.'s in their Pistons for many years
4.) Silv-O-lite can see no reason to change them though, because A.) they keep selling, and B.) to do so would be admitted they know of the problem.
So, in a nutshell...
they just keep building and selling them with the incorrect publishing counter data, same as Federal Mogul does with their 345NP Piston offering which is also extremely low compression.

Bottom line....
it has been a case of "buyer beware" for decades now.... hence why when you came on here with your "Engine build thread", on a Car Site specifically about Mopars and the Engines, and in the spirit of trying to help another car enthusiast.... we were trying to WARN YOU !

Some data that has already been "stickied" here on this site, but I will recap again.
http://www.dodgecharger.com/forum/index.php/topic,118292.0.html

Here is some handy information to that educational end:
1.) An un-milled "stock" 440 Engine Block.... requires a Piston Compression Distance spec of about 2.085" to reach "TDC".
6.76" Rod Length + 1.875"(1/2 Stroke length) + 2.085" height Piston = 10.720" 440 Block Height.
2.) Each .010" less than 2.085" of Piston Spec Compression Height.... ADDS approx 2.4 CC's of Volume to the Final Clearance Volume for calculating actual static Compression Ratio.
3.) Most, if not all "open" Chamber BB mopar cast iron heads after rebuild, will come in around the 88 CC mark. Again here.... actual CC'ing to verify is always best, but 87-88 CC's  is a good base assumption without milling.
4.) pretty much all "composition" style Head Gaskets are approx 10 CC's of Volume.

From the above....
it is pretty easy to see, that a Piston with a 1.969" Compression Distance like even the "high" offering from Silvolite(the HIGHEST stock cast piston I can find in the marketplace)
see here:
https://www.uempistons.com/index.php?main_page=product_silvolite_info&cPath=6_25_27&products_id=1643&zenid=86510ba966b1a2d67c36e77071ecd75a
will be,
about .110" DOWN the hole at TDC on an UN-milled 440 Block, good for about 11 X 2.4 CC's or about 26 CC's of Volume

Now add 10 CC's for the head gasket, and 88 CC's for the Head to the above 26 CC's, and PRESTO !
We now have a TOTAL Clearance Volume for calculating static Compression Ratio of 124 CC's

(Swept Volume PLUS Clearance Volume) divided by (clearance Volume) = Compression Ratio
.030" Overbore 440 = 914 CC's
(914 + 124) divided by 124 = 8.4:1 Compression Ratio.
and that's using the HIGHEST compression height stock cast Piston I can find !
Only wimps wear Bowties !