Former lurker now on board: Pick me a cam, please!

[68n70]

Been reading your forum for some time and have really enjoyed it.  There are obviously a lot of knowledgeable people on board and could really use your help! 
I have  a stock 440 I'm putting back into my '68 and would like to change the cam as it has a MP "484" in it now and I've never really been pleased with it.  It's bone stock bottom end, with template ported 452's, roller rockers, street dominator intake w/ 750 speed demon and FBO ignition, Hooker super comp headers w/ 2.5" exhaust.   It's a full manual auto w/ a Gear Vendors unit, 3500 stall (I also have a MP 2500 stall if you think it might be ok) with a gear to be determined. (Right now it's a 3:91, but I have access to 4:56, 3:55, and possibly a 4:30 if I'm lucky).
What do you think for a good performance cam?   What gearing?  3500 stall ok?
I appreciate any help with what I know is a lot of questions.
       

[Challenger340]

Welcome aboard ! You'll find lots of great resources on here.
Just to clarify, you say "bone stock bottom end".

Does that mean you have the "original" Comp. Distance 1968 Pistons ?  Just curious as to how much "wind" you have in the cylinder ? Do you know the compression, or how far down the hole the piston is at TDC ?
A non-rebuilt engine with the originals, or "rebuilder" stock pistons ?

With the "stock bottom end", does that mean you probably don't wish to rpm the motor very high ?  52-5500 rpm on the stock rod bolts ?

"Hooker Super Comp" headers,  1 7/8" primaries ?

I'm sure you'll get some good reccomendations, these guys have a TON of experience. Just trying to clarify a few items that may help.

Again, Welcome !

Bob out.

[mikepmcs]

I'm betting the gurus will be suggesting an engle k56 or k58. 

welcome home!

v/r
Mike

[68n70]

Thanks for the warm welcome!
Sorry for the lack of info Bob, just goes to show how much I know about this sort of thing.   It's actually a '70 motor factory fresh, that is, it's never been apart.  Using my ultra high tech and super accurate spark plug feeler gauge, the dish pistons look to be about .090 in the hole, although I did mill the heads .020 and used steel shim gaskets to up the compression somewhat.  The headers are indeed 1 7/8" and I agree, I don't know how long it would last going much above 5500.
I've read on here that the Engle cams seem to be a popular brand, however I have absolutely no experience with them.  But obviously I'm a ham n egger when it comes to motor work so I'm wide open to whatever the real motor builders advise!   
Thanks again!!!

[Rayzor]

If you look down a few posts you will see my 440 combo with the engle K54 grind cam.  With your steeper gears and converter you could probably go upward to the K56 grind  for a bit more power. While I am not much help on the specs and ins and out, I can tell you I spent good time going over my combo with Mark Engle. He wanted to know exact details about the car and its uses before he made his recomendations. So you may want to give them a call. Also, welcome to the board.

[Challenger340]

Sorry, I can't be of any help here, I'm just not familiar with 440 "dish" pistons @ .090" down the hole ?

I think this is fairly low compression ? but, again, I don't know.

Apologies, I don't have anything to offer. I'm clueless about the dish.

Anybody, Ron, Chryco ? you guys know what the C.R. would be here ?

[Runner]

a crane 272h would be a nice stockish idle and make ok power.  i have one in a 9.4-1 comp 383 in my 68 satellite and its a real pleasure to drive.   i put a crower 271 in my daughters 446 in a 69 superbee clone.  however im having a little carb issue with it right now, so i dont really have an opinion on that one yet other than, it was expensive compared to comp, crane ect... i dont think id go that route again for that very reason.  to be honest,  people have had decent luck with the summit cams. in your shoes i might be very tempted to give one a try.

[firefighter3931]

I think this is fairly low compression ? but, again, I don't know.

A slug that is .090 below deck even if it's a flat top is gonna have low static compression. Without measuring it's a guess at best but assuming those measurements are correct it will be in the 8-8.5:1 range. That explains why you've been dissatisfied with the MP 284 hydraulic cam (238*@.050= too big)....it is poorly matched to the engine, inmo.

Crower makes a nice line of "off the shelf grinds" that would work well in this engine. The HDP271 grind would be a step in the right direction....it's a 112* lsa and i would install it at 108*. I'd keep the 3.91's and go with the 2500 converter. This cam will make a lot more bottom end power and pull good to 5800 rpm which is about as high as you want to go with a stock shortblock anyway.

The rest of the parts look well matched. 

http://crower.com/misc/cam_spec/cam_finder.php?part_num=32242&x=41&y=12



Ron



Ps. Welcome to the site 

[68n70]

Ron,
Thanks for the reply!  That sounds like sound (!) advice.  I know the compression has always been its downfall but until I can scrape enough together to do a rebuild, I'm stuck with it.  Hopefully that will change in the near future and I can bug you guys on an even larger scale with advice on a full engine rebuild!!
I do have a couple follow up questions though.  I'm curious why you advise the 3:91's over a deeper gear.  I thought with the gear vendors unit, I might get away with something like a 4:30 or possibly a 4:56 and give it even more of a shove on the bottom end while still having enough drop at the final drive for civility and driveability.  Am I thinking of that correctly or am I way off base?
Also, and this is purely for my own understanding, is the reason you recommend the mp2500 stall that this cam's power range starts very low, therefore I'd be wasting powerband if I had the bigger stall? (I don't see on the info sheet where it starts and drops off)
Thanks again for your help and patience with my ignorance on cam science!  It's obviously not my strong suit!!   

[firefighter3931]

68n70,

The 2500 stall is better matched to the powerband of that cam.....you are correct. Something else worth noting ; when highway driving, it helps to keep the converter close to the actual stall rpm at cruising speed. This will avoid the creation of excessive heat and keep the transmission happier. A 3500 stall with a 2500 rpm  cruise speed is a bad combination, inmo. The other mitigating factor is the powerband of the cam....which is better suited to a 2500 stall....there's no point in wasting all that bottom end torque ! 


As for the gear selection there are several factors to consider. Tire diameter plays a significant role as well as desired cruising speed and how much rpm you want to be turning at that cruising speed. Ideally, you want to be in the lower end of the powerband at cruise speed so roll on power and throttle response is right there when you need it. Hope that makes sense.

How tall are your rear tires ? How fast would you like to cruise at ? What is the OD ratio of the GV unit ?



Ron

[68n70]

Thanks for the follow up, Ron that makes perfect sense.
As far as the rest, my tires are 28" and the GV final drive - I don't know for sure.  I bought it from a friend and it is an older model.  I've looked through the manual and see nothing that says what the final drive is.  I went on their site and my exact particular model # isn't listed anymore. (probably superceded).  I can only find one reference to final drive for the current 727 model and that is .78.  Does that sound right??
The majority of my driving is not done on the freeway, more around town and 10-20 mile drives here and there.  I guess 60 mph would be around where I'd cruise at, more or less.   
Hope that helps.
Thanks again.

[firefighter3931]

The .78 sounds about right from what i've read. Maybe you could contact GV to confirm. 

Ok i used a calculator to show you some numbers based on a 28in tire diameter ;

3.91 + 28in tire diameter + GV (.78)

60mph = 2200 rpm
65mph = 2380 rpm
70mph =2560 rpm
75mph = 2750 rpm

4.30 + 28in tire diameter + GV (.78)

60mph = 2400 rpm
65mph = 2600 rpm
70mph = 2800 rpm
75mph = 3000 rpm


Personally, i would go with the 3.91's based on these numbers. The reality is that when you're on the hwy, cruise speed is more likely to be 65-70 mph which would put you right where the engine is in it's lower end of the powerband and you won't have to buzz the engine too hard to keep up with traffic. Nuthin worse than getting passed on the hwy by a fricken Honda !  You'll still have the 3.91's for around town "stoplight to stoplight" action. 


This should also illustrate why the 3500 stall is a bad match for an OD unit. 



Ron

[68n70]

Ron,
Thanks for that info, I see what you mean. 
Alright, I've printed off the cam info and think will set it up just as you advise.  One more question and I'll quit bugging you, where can you order Crower cams?  Are they sold exclusively from them?  I could not find them at my usual haunts (summitt not at all/jegs not that part number).

[firefighter3931]

Summit carries the Crower line....they list the next grind up (32243) but for some reason don't list the HDP271  Give them a call, it might not be a stock item and have to be ordered in. Your current valvsprings & rockers will be fine with this cam.  Don't forget to order a new set of lifters with the cam....i'm pretty sure the cam & lifters are not sold as a package.

Breaking in the cam is critical, you will need some additives and good oil ! If you need help with this just ask. 



Ron

[mikepmcs]

Ron
Sorry to hijack but i'm going to order my engle k56 as you suggested a while back and was just wondering what else i need to get with this.  I'm sure lifters but what about valve springs rockers etc... Is this something i should look into as well and if so do you have any suggestions.  383, pretty stock but rebuilt(not by me) and has about 300 miles on it so everything is pretty much new in there. 750  hp, performer mani, 727 2500 stall, soon to have a built 727 by RD and a set of 3.91's in the rear(it has 3.23's right now though)
Also, do you have a suggestion for additives and oil for break in that you use and wouldn't mind sharing.  I think you put that in another post but i can't remember.
Sorry if you are having to repeat yourself, but i appreciate your time and patience.

thanks
v/r
Mike

[firefighter3931]

Hey Mike, without knowing what valvesprings are in there now and what the open/seat pressures are....it's difficult to say whether they would work or not. If in doubt, order the matching set from Engle when you get the cam and lifters. The stock rocker arms and pushrods will be fine as long as they're in good shape.

For breakin, GM EOS (engine oil supplement) is loaded with Zinc & Phosphorus....both critical anti scuff additives that the new oil formulations are sorely lacking. Shell Rotella-T 15/40 diesel oil works well as a breakin lube. Lately, i've read that the diesel oils are losing some of the zinc/phosphorus content (reduced ppm values) which is not great news for us flat tappet cam users. From here on out it would be advisable to run a bottle of EOS with every oil change due to these EPA mandated oil reformulations....it's just insurance against a cam failure.



Ron

[68n70]

Ron,
Thanks, I see them in summitt now (not sure where I was looking before!).  I'll contact them to see if your cam is available and if not, hope you don't mind a "second choice".  I'll let you know...
The post above answered my next questions about break in.  I'm feeling somewhat better about my engine knowledge as I was going to use the EOS and the diesel oil (!) already.
Would you use the diesel oil all the time or just on break in?
Thanks in advance for all your help, it's great to be able to get advice from someone who is both pleasant and Mopar knowledgeable/specific!! (a rarity where I come from!)   

[firefighter3931]

Would you use the diesel oil all the time or just on break in?
Thanks in advance for all your help, it's great to be able to get advice from someone who is both pleasant and Mopar knowledgeable/specific!! (a rarity where I come from!)   

To answer that question ; INMO there is nuthin wrong with using diesel lube all the time. Diesel engines operate under the harshest conditions and live for many years using that type of lube.  In the past. Rotella, Dello and other fleet type diesel oils had lots of the good anti scuff additives but the EPA has mandated reduced levels of Zinc/Phos so we need to add our own (EOS). 


You're welcome for the help. 



Ron

[mikepmcs]

Ron
What kind of seat pressure am i looking for? I'm thinking 125ish   and the open is around 300+  I'm guessing i'm stockish right now with about 114 and 9:0 comp ratio, am i way off here, but it's a stock rebuild so......

[firefighter3931]

Ron
What kind of seat pressure am i looking for? I'm thinking 125ish   and the open is around 300+  I'm guessing i'm stockish right now with about 114 and 9:0 comp ratio, am i way off here, but it's a stock rebuild so......

Mike, the Comp Cams # 911 valvespring works great with just about any hydraulic cam and some milder solid profiles. The Engle sticks are a little more agressive so a stock spring won't cut it. INMO, 125-130 on the seat and 300-325 open should be in the ballpark....but verify those numbers with Engle, just to be safe. 


Ron


Ps. The K56 is the right cam for your 383, inmo. I would have it ground on a 110* lsa and install it on a 106* intake centerline which is 4* advanced. This cam has 15* less duration at .050 valve lift than the MP 484 and will make a lot more bottom end power and idle much smoother.  The shorter stroke B engines don't make the big torque numbers that 440's do so keeping the cam timing conservative is a step in the right direction. The dual plane manifold will also help in this area as well. 



Ron

[mikepmcs]

Ron
Thanks again.
I'll get the 56 and the grind you specify. 

v/r
Mike

[firefighter3931]

You're welcome Mike....i think you're gonna luv that cam....but your tires are gonna hate you ! 



Ron

[mikepmcs]

Ron
One more thing if you don't mind.  I am going to purchase my cam degree kit to get ahead of the game and there is one on ebay for $51+$19s/h buy it now but no video and i was thinking that one with this video for $33 by Wayne E. Partridge.

http://cgi.ebay.com/ebaymotors/Understanding-Cam-Valve-Train-Degree-Your-Cam-DVD_W0QQcmdZViewItemQQcategoryZ33614QQihZ011QQitemZ320078012247QQrdZ1QQsspagenameZWDVW

or..

I can purchase a comp cams degree kit with video for $109 total. 

My question is..

Is the video in the comp cams very detailed and sufficient if you happen to know, or anyone else out there for that matter who might have seen it, or have you heard about the Wayne Partridge dvd.

Just looking at my options to get the most bang and knowledge for the buck.

Thank You for your time.
v/r
Mike

[firefighter3931]

Mike, have you looked on the Comp website ? 


http://compcams.com/Technical/Instructions/Files/145.pdf



Ron

[mikepmcs]

Ron,
Yes sir I have, I have downloaded all the tech info I can find to look at em all, so I miss nothing.  I was just hoping to see a video too.  I'm a hands on person so reading sometimes doesn't do it for me, although I'm sure I could follow this as it's pretty detailed. 
I'm just one of those guys who likes to see it done once and then i'm golden.
That one video by Wayne Partridge supposedly shows all the degree/timing and bushing stuff that goes on as well.  It probably couldn't hurt to view it anyways, i'm just trying to find a used copy for cheaper.
Thanks for the link and assistance as always.

v/r
Mike