Im looking around for heads to use on my shortblock and so far it looks like I need 110cc or smaller chamber heads to get the compression up. Im shooting for around 10:1 compression. The car will be street/strip or strip/street(I have good tolerance for nasty engines).


6.135 rods
L2399 + .060 pistons - 13.8cc domes
stock 4.00 stroke
4.060 bore
.015 approx inside the hole(not zero decked)

I need gasket thickness and bore diameter for gaskets that I can possibly use(AL heads)

So far Im getting between 8.9:1 to 9.1:1 static with a 4.1-4.5 bore gasket and .039 thick gaskets.This is with 100cc chamber heads

Am I doing the calculation right?It seems like everybody I ask when I say 100cc heads and 13.8 domes gets me closer to 10:1

So dar it seems the closest heads are either the bare 100cc Edelbbrok RPM or the 106cc Vic Jr.

Option 1 - Or am I just better off to change the pistons and get 119cc heads?(Patriot BBC heads can be had for half the Edelbrocks) - The engine is externally balanced so I dont think I need to do anything special just to change pistons..

This calculator says 7.71cr

http://www.rbracing-rsr.com/compstaticcalc.html

I it was 0 decked you'd get your 10:1

Daz you have the bore size wrong for a 454 , standard bore is 4.250, so .060 over would be 4.31

Part of the problem with a BBC is that it's tough to get decent copression with a stock stroke [GM never should have made the 454 they should have built it with a 4.25 stroke to begin with ] The chamber in the head is just way too big and the 100cc heads won't fit most dome piston .

If you change the pistons Daz you are going to have to balance the motor .
Externally balanced just means that there isn't enough room inside the crank case to put all the required wieght in the crank so extra wieght is added to the balancer and flywheel
Bigger domes usually mean heavier pistons so it changes the balance wieght

About th e pistons. I forgot to mention that if I get bigger dome pistons with the same weight it should be OK

It seems like 110cc would be around 9.75:1 with a .039 gasket anyway so I dont need a 100cc head.

I guess it will be the 110 Edelbrock RPM or 113cc Brodix RaceRites then

How bad does milling the head affect valvetrain geometry? I had TFS heads before that was milled by a lot and I had to cut the intake and get special pushrods to correct geometry.Maybe Ill just stick to basics

You put in some wrong info somewhere because .015 difference in deck hieght doesn't change compression that much

Engine geometry is a pretty grey area even if nothing has been done to a block and heads you may have to machine a new intake manifold [I find that most are too big ] the reason behind this is the engines original production tolerences [everything has an upper and lower limit for size ]
So when the manifold companies make a manifold they make it to the upper limit [wide ]this is because it's easier to take matterial off the manifold than to put it back on I've tried running the resurfacer backwards and the parts don't get any bigger

As far as pushrods go they should be the last thing you buy their length and the geometry are effected by heads, cam, rocker arm design' was the block cut,heads machined , etc just about everything can make a difference . that's why you can buy SB Chev pushrods in .050 increments .
I've seem motors where the intake pushrod and the exhaust were .100 different in length .

I wouldn't have thought so either but all I changed was the deck ht and the compression went way up, too much up. Maybe that calc is f'd. LOL

maybe you didnt made the piston volume a negative

Or accidentally moved a decimal point [$h!+ happens ]

10.1:1 with a 106cc head
10.36 with a 106cc head and 0 deck
http://kb-silvolite.com/calc.php?action=comp