another compession question.

[hard-charger]

hi! ok, I've got a 440 .30 over.  my compression is supposed to be around 10 to 1. maybe more, but with my 906 heads being open chamber. the effective comp. is lower. don't know what it is exactly, cause the chart I was going by measured comp. with 88cc, 84cc being 10.5 to 1, & 78cc chamber heads. & so on.....
so, I finally am buying heads for my ride. but I've read 100 time over about alumminum pressure bleed.  so would I need to buy 11.5 to 1 pistons to achive my goal of 10.5 to 1 comp.?
I don't wanna kill my low end, cause I have a pretty mean cam in it right now. any help would be of the highst value! thanks!!

[firefighter3931]

How far in the hole are your pistons ? I don't think you'll be happy wit 11.5:1 even with aluminum heads.  I would shoot for 10.5:1 if you want to run on pump gas and run full ignition advance. A flat top piston at zero deck with an 84cc closed chamber and .040 head gasket is ideal for a street/strip pump gas combo. 


Ron

[hard-charger]

we are at zero on the decks. slighty milled 906's. not sure how much got cut off. but its enough to change the geometry of the intake. does zero deck throw off the geometry to? could be a combo of both. the block did not need ecssesive miling to get it to zero. but the heads arnt even close to 84cc.
anyways, so a zero deck .40 head gasket & 84cc eddys would do the trick?
we are running a engle kv3 intake, kv4 exhaust, on a 110 centerline. mabey 108. I can't remamber.
410's in the rear
2 600 holleys on a wieand tunnel ram.
1 7/8 super comps. thu 3in dynomax bullets. (just got those bullets, haven't herd them yet)
3800 stall, maual valve body trans.
as for the heads. we are working on that now. thanks!!!!

[firefighter3931]

does zero deck throw off the geometry to? could be a combo of both. the block did not need ecssesive miling to get it to zero. but the heads arnt even close to 84cc.

HC, most aftermarket pistons have a pretty descent compression height (~2.065) so there won't be alot coming off the deck surface to square everything up. Mine required a .020 cut. The factory head gasket is .020 so when you go with a .040 head gasket that puts right back where you were before if not very close. Now, depending on how much you mill the heads you could have allignment issues....for every .010 off the deck surface you need to take .012 off the intake surface to maintain proper alignment....or you can cut the intake manifold. Most opt to cut the (head) intake mounting surface so that the manifold will fit other engines, that haven't been modified. 


With the KV3/KV4 i would shoot for 10.5:1 with the closed chamber aluminum heads. The cam in mine is bigger (more duration) and it made lots of bottom end power on the dyno with 10.5:1 static and with .040 quench it runs fine on UL 93 pump swill. I don't see you haveing any issues with the same kind of combo. 


Ron

[hard-charger]

what heads were you running?

[firefighter3931]

what heads were you running?

Performer RPM's 84cc closed chamber. Mild porting and comp valvejob with 30* backcut.



Ron

[hard-charger]

hey thanks again! I had another qustion about your engine.
with the decks milled & with the eddys, did you have to buy custom length pushrods?

[firefighter3931]

hey thanks again! I had another qustion about your engine.
with the decks milled & with the eddys, did you have to buy custom length pushrods?

HC, the deck was squared up and milled .020 below blueprint spec (10.725) to achieve the zero deck with the speedpro 2355 6-pack pistons. Using the .040 gasket brought things back to where the factory should have had them because the factory head gaskets are the steel shim .020 gaskets. We used out of the box crane pushrods with the Harland Sharp roller rockers....nothing custom required.


Ron

[hard-charger]

are you running tti headers. or do you know how the 2in. super comps might fit.
I saw the new mopar/eddy heads. but they have an added cost.
I have 2in primery supercomps unused. I'd like to use them but I've heard 1 7/8 super comps have issues. but I've herd nothing about 2iners.
It might justify the exrta cost if anybody has any info. thanks again

[firefighter3931]

HD,

I have TTI headers for mine but the 2 in supercomps will fit. We had those on mine when it was on the dyno (2 in supercomps) as well as the 17/8in comps. The 17/8 in supercomps are a no-go with angled plugs...don't even think about it. Both sets of hookers required some clearancing on a few tubes....nothing major. The MP edelbrock heads would be a better fit with a Hooker header because of the straight plug issue. Personally, i would go with those if you don't want to modify your headers. 


Ron

[hard-charger]

thanks!
what size are the headers you have now? & how did the 2in supercomps. perform against 17/8? thanks again!

[firefighter3931]

I have 2 in TTI's going on mine but i was planning on going to a stroker in the future. The 17/8in headers made slightly better torque than the 2in tubes. If you've got the 2in headers just go ahead and run them.  With the tunnel ram and Engle stick.....the 2in tubes will make more top end HP but might give up a little Tq down low.



Ron

[hard-charger]

thanks. now I got another question. 
how do you think the eddy rpms stack up against indy ez's. or eddy victors? on an engine like mine?
I see the victors got good flow#s ez's are close to the victors.
I'm looking hard at the indy ez heads for my engine.
I dobt know anybody with an engine like mine with indy heads. they all got eddy rpms. thanks again!

[firefighter3931]

thanks. now I got another question. 

I had a feeling this one was coming 

OK,

All of the heads have their place in the performance world....it just depends on what you want. The ez's and victors have smaller chambers (75cc) so that might cause problems with your static compression ratio if you want to run pump gas. Both the EZ & Victor are ~20cfm better out of the box with lots of upward potential but that means porting and $$$. The big power numbers with those heads will mean a max wedge intake port window and a new manifold. The bigger intake port will reduce velocity at lower engine speeds and make the engine sluggish out of the hole....it's a tradeoff. 

For a 440 based combo, my preference is for a smaller, efficient high velocity port to keep it torquey, especially if you plan to street drive it. The RPM heads will make very good power, even on a 500ci street motor (600hp +) with some mild porting and the right combo of parts. Fully ported on a 500ci stroker with big compression....the RPM's can make 700 Hp.

The Victors require an offset intake rocker....those can be expensive, especially for the good ones (Harland Sharp $1000.00) Port volume is 280cc.

The EZ's take all stock rocker gear and have internal oiling, but they are really a max wedge head with a standard intake port. The openings are closed down to 906/452 dimensions right at the intake opening....a 1/4inch past the opening they open right up creating a port volume of 265cc.

So, it just really depends on what you're looking for and if you plan to go a lot bigger. If a 500ci engine is in the future, the EZ's or Victors will make more power but you'll have to port them to get there. These heads could potentially cause problems with your current combo by increasing the compression too much to run on pump gas....if that is an issue for you.



Ron

[hard-charger]

ya. I was thinking down the road when it was time for a rebuild that I was gonna go with a stroker kit.  so I was looking at the EZ's.
the victors with the added cost of offset intakes /finishing made them seem pricey.
I was looking for that high velocity intake head tho. to keep it somwhat streetable.
do the ez heads have that high velocity intake?
I really don't know all that much about them. except they look like they got some nice flow #s & mad potential. & will they be ok on my engine for now. I'd like to have all the parts ready to go for future plans. but defanatly don't wanna drive around/race at the track, all lame & sluggish. if the eddys can get me up there & drive good now then, hmm? mabey eddys it is?
thanks again!

[firefighter3931]

HC, for most street applications i would say that the EZ's are a little on the large size with 440 cubes. In your case, running a tunnel ram and big  solid cam with deep gears it won't be that  noticable as compared to someone using a milder hydraulic grind with a dual plane and 3.23 gears. If you're planning on a stroker in the future then the EZ's are the way to go....but you will have to port them ang go with a max wedge port sized intake manifold when you upgrade....to get the most out of those heads. 

The only pitfall will be compression with your current shortblock combination. Any chance you can get a deckheight measurement ? That info would help to determine the proper course of action. I am making the assumption that you want to run this on pump gas. Is that the case ? There are options for head gaskets with larger bore diameters and thicknesses to help pull some compression out of the motor...if need be. 



Ron