91RS5speed

I built a 383 several years ago and it was set to have 64cc heads. With 64cc heads it would have 9.5:1 compression. I ended up getting a set a 113 ZZ4/Corvette heads that have been milled to 57cc. My question is what would my compression be with going from 64cc heads to 57cc.

daferris

iTrader: (8)

Because of variables like gasket thickness and deck height best to calculate it yourself. this is a link to a decent tool that is simple but accurate...
http://www.csgnetwork.com/compcalc.html

NoEmissions84TA

iTrader: (1)

Many variables, but I came up with 0.7 increase.

Worry more about your Dynamic compression ratio.
The IVC point of your camshaft determines this.

skinny z

Yes. About 7/10ths.
And the dynamic compression ratio is the ultimate target however I'm curious as to how you came up with you're posted compression ratio in the first place.

91RS5speed

When I ordered the rotating assembly I told the salesman at Summit I wanted a 9.5:1 with 64cc heads. I have been looking for the receipt to find out what pistons were ordered. They are dished but, how much I am not sure. I did find the cam card. I do not see IVC listed on the card though.

Cam Card attached

skinny z

Without information like the piston dish volume, piston below deck distance and the head gasket thickness, you could be a long way from 9.5:1. In either direction.
Is the engine in running condition now?

skinny z

IVC is listed as INT: closed 35 ABDC. (Can't tell for sure if the number is a 35 or not).

91RS5speed

Alright I found the info on the dished pistons. It looks like they are +16.00cc. Do you guys have an estimate on HP on this setup?

383
113 vette heads
mini ram w/bbk throttle body

Lift .487 intake ,495 exhaust
Duration @ .050 212 intake 218 exhaust
Lobe separation 113.0

NoEmissions84TA

iTrader: (1)

Using the calculator above, I came up with this:

That CR is too high for your camshaft.