I am looking to throw some 243's on my 5.3 but I can't seem to get any help on milling. I know the 243's have a stock chamber size of 64cc. I know its probably a lot of milling, and maybe not a good idea. But I was wondering how much milling would need to be done to reach a chamber size of 59cc? Also what would this put my compression at on a 2006 5.3 with the GM hot cam.

 

https://www.performancetrucks.net/forums/search.php

type in the search "milling"

 

I tried the search... It's just I can't find too much on the 5.3's with these heads. However, I read that if I mill them .40 that would give me a chamber size of 58cc. Is this true? If so would my CR be somewhere around 10.5?

 

- Approximately 0.006” per 1-cc.

 

Ok awesome, that helps. Now how would I go about finding out my CR?

 

i would search other threads to find out similar setups. and theirs compression calculators on the net. i just googled a few, but they need alot of info.

 

Can someone please look this over and validate it for me?
I think I have figured out that I need to lose 5cc's from the 64cc chamber of the 243's.
So if I wanted to get down to a 59cc chamber I would need to mill these 0.030 correct?
Which would then by that chart, put my CR at about 10.5:1.
What is the maximum tolerance of these heads? Can I safely mill them?

 

For every .007 you mill you'll lose close to 1 cc.......... You'd need to mill .035 off the heads to lose 5cc or close to it...

 

Ok cool. So if I wanted 58cc chamber I would need to mill .042?
64 - 58 = 6cc
6 X .007 = .042

This would put me at close to 58cc's correct?

Can I safely mill my heads .042?