wat to do with 243 heads?

[oleshifty]

When i was looking into 243's....even milling down the max, the compression was still going to be lower then my stock 862's. Was the only reason i got a set of those worked/milled down to raise compression above stock.


Lambo is running 862's and I THINK he's one of the fastest 5.3's. His guy is doing mine too. If the block was a 6.0, by all means, 243 will flow better. Sure most of you guys here know more then me, but few months ago I did tons of research and talked to a few machine shops, and they all agreed 243 would make me slower, and recommended working factory heads IF staying n/a. I went with a milder cam, so that could be part of the reason as well.

[chvy=power]

i bought them off yellowsierra02 for $450. well i sure dont wanna spend all my money on a set of heads thats gonna make me slower...

[chvy=power]

well from what i'v found approx. .0065" milled off the head will take off 1 cc. the 243 heads have a 64.45cc combustion chamber and the 862 heads have a 61.15cc combustion chamber. So after some math it looks like it would only take around .022'' of milling to get the 243 heads to the same compresssion ratio as the 862 heads

[PitchBlackC3]

Do all the newer 5.3s that have the 243s have flat tops or what's the deal there?

[oleshifty]

yes, the 5.3 HO have the 4.8 pistons. If my milled 862's don't do it for me, that will be the next upgrade

[chvy=power]

if i shaved the heads .030" will the intake bolt holes still line up??

[pl4yboy]

Yes...

PS, my 5.3 is the LMG with 9.9 CR and 243s.