Ok guys, not good with math so someone help me out please. Got a stock block LT1 and i am going to be installing a set of gtp stg.2 heads along with a gm847 bumpstick to put in the car. Currently running 5# of boost. The problem, the heads have 52cc chambers and i beleive stock is 58cc. What is my compression going to be and am i still going to be able to run 5#'s? I really want to try and push this thing as far as I can on the stock block. I wanted to run 7# but i know i can't with the small chambers. Any help is greatly appreciated.

 

This is what i came up with:

Stock Motor
stock = 10.5:1
5psi = 14.07:1
7psi = 15.50:1
New heads
stock = 11.2:1
5psi = 15.05:1

so essentially i should be able to run 5psi and should be a little less than the same as 7psi on a stock setup, right??

 

I believe stock LT1 heads were ~53cc's from all the information I have looked up. so you may not be raising compression as much as you think. best way to find out though is to have the heads CC'd to know exactly what you static compression ratio will be on the new setup. what heads are you gonna be running? have you already purchasd them? if not you may give the trickflows a serious look.. I am running them, they have a 62cc chamber which helps drop the SCR down some and are very affordable for the product your buying.. they have a great port design, and untouched from the factory meanign installed as cast no porting on 14 pounds on my car and a STOCK camshaft pumped out 514/570 at the wheels. I believe that number will be higher on the same amount of boost once the fuel system is finished being fixed as towards the end she had leaned out to almost 13.5 AFR.

Chris

 

I've also heard that the stock heads are around 52cc's. Check out the compression calc here:

https://www.camaroz28.com/services/calcs/

 

The stock heads are 54cc's. When I was building my F.I. 355, I had the head porter work the chambers over to get them to 56cc's. It makes a difference with compression and detonation.