Help calculate my comppression ratio
Thread Starter
Instructor
Joined: Oct 2004
Posts: 118
Likes: 1
Help calculate my compression ratio
I am rebuilding a 454 that is bored 30 over, with stock stroke, the heads are open chamber large oval port heads casting number : 6272292 ( 1971 402 - 454 LS3-LS5 ) I have searched the internet and cant find anybody that knows what the head CC is for sure, I have read that they are 105.cc, 112.cc and 116.cc ??? the heads have been milled 10 thousands, the pistons are Speed-Pro H581CP 30 they have a .340 dome, the piston specs are here : http://store.summitracing.com ( search H581CP 30 ) , I will be using stock type fel-pro head gaskets, Thanks, DAVEWSC
Last edited by DAVEWSC; Oct 11, 2007 at 07:06 PM. Reason: BAD LINK
Burning Brakes
Joined: Jul 2001
Posts: 853
Likes: 0
From: Foxfield, Co
Heres a thread where someone was looking at those same head numbers. Seems to be a little confusion about them.
http://forums.corvetteforum.com/showthread.php?t=848910
http://forums.corvetteforum.com/showthread.php?t=848910
Thread Starter
Instructor
Joined: Oct 2004
Posts: 118
Likes: 1
Heres a thread where someone was looking at those same head numbers. Seems to be a little confusion about them.
http://forums.corvetteforum.com/showthread.php?t=848910
http://forums.corvetteforum.com/showthread.php?t=848910
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
I am rebuilding a 454 that is bored 30 over, with stock stroke, the heads are open chamber large oval port heads casting number : 6272292 ( 1971 402 - 454 LS3-LS5 ) I have searched the internet and cant find anybody that knows what the head CC is for sure, I have read that they are 105.cc, 112.cc and 116.cc ??? the heads have been milled 10 thousands, the pistons are Speed-Pro H581CP 30 they have a .340 dome, the piston specs are here : http://store.summitracing.com ( search H581CP 30 ) , I will be using stock type fel-pro head gaskets, Thanks, DAVEWSC
+33cc dome volume, 0.025" down in hole.
104 ~ 11 3/4:1
111 ~ 11:1
115 ~ 10 1/2:1
take a look at STL-H426CP30 ... 0.100" dome, +10.5cc dome volume, 0.025" down in hole ... with those & a thin gasket you'd have better quench and scr range of about 9 1/4 - 10:1. I dunno what cc your heads were/are.
Last edited by jackson; Oct 11, 2007 at 10:17 PM.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
The chamber size varies by year. Check post #5 http://www.clubhotrod.com/forums/showthread.php?t=29384
Advanced
Joined: Sep 2006
Posts: 78
Likes: 0
From: Nashville NC
I am rebuilding a 454 that is bored 30 over, with stock stroke, the heads are open chamber large oval port heads casting number : 6272292 ( 1971 402 - 454 LS3-LS5 ) I have searched the internet and cant find anybody that knows what the head CC is for sure, I have read that they are 105.cc, 112.cc and 116.cc ??? the heads have been milled 10 thousands, the pistons are Speed-Pro H581CP 30 they have a .340 dome, the piston specs are here : http://store.summitracing.com ( search H581CP 30 ) , I will be using stock type fel-pro head gaskets, Thanks, DAVEWSC
http://www.bgsoflex.com/auto.html
Drifting
Joined: Jun 2006
Posts: 1,912
Likes: 12
From: Schaumburg (Chicago) Illinois
I can't believe I am giving advice on this topic but maybe I am learning a thing or two. To be absolutely sure, you can buy a kit from Summit that measures the volume of the heads. Cost about $100 though. There is a cheaper one but I am not sure how accurate it is. Or maybe you can make one yourself if you look closely at the pictures.
Search for Cylinder head CC kits
SUM-911581
Search for Cylinder head CC kits
SUM-911581
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
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Le Mans Master
Joined: Apr 2005
Posts: 6,357
Likes: 427
From: Seattle Area WA
I'm with Lars, I used to use a syringe I bought at a farm supply store, but I just picked up a cheap buret. I think the syringe is actually easier to use. I also use a scrap piece of glass and grease to seal it down to the head.
Thread Starter
Instructor
Joined: Oct 2004
Posts: 118
Likes: 1
I decided last night to CC the heads myself that way I know for sure what I got , My wife is a pharmacist and she supposed to bring home a syringe for me, but they only have 10 CC syringes, I never thought about a farm store, now I just have to find a piece of plexiglass, I would take it to my local machine shop but who knows how long he would take, He was doing the machine work on this motor (under the table) and I just got it back after almost 2 1/2 years, when he did my 383 a few years ago it took him 3 months and I thought that was a long time, but I took my original L46 motor to him the other day and he had it back to me in about 2 weeks, which I was in no hurry for but I figured, I may want to put it back in before I sell the car someday, I shouldnt complain he does excellent work and he saves me alot of $$$, If I was in a hurry, it would cost me twice as much but I would get it back a whole lot quicker, thanks everyone for the help, I appreciate it, DAVEWSC
Drifting
Joined: Jun 2006
Posts: 1,912
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From: Schaumburg (Chicago) Illinois
Le Mans Master
Joined: Apr 2005
Posts: 6,357
Likes: 427
From: Seattle Area WA
$17 for a free syringe from your local pharmacy and some vasoline to take the sting away..
It's all you need though. You can also buy decent plastic 100ml burets on Ebay for around $25.
It's all you need though. You can also buy decent plastic 100ml burets on Ebay for around $25.
