I have a set of 561 heads off a 97 Z28 engine, are these worth porting compared to the 643 heads? I'm building a 355 forged motor and still debating to go with stock ported heads or aftermarket heads.
Forget which head is better.Nab, that's not what I've heard. I'm pretty sure the later heads are not as desirable for porting and flow less than say the 643's.
NAB is exactly correct..They're decent heads. I ported a set and ran them for years.
Don't let these guys fool ya.
If its what you got USE IT!
That is not what was posted. Don't read something that is not there. I agree with Dwayne. I'm not stating they not worth porting or using. I'm not disagreeing that they are not "good" heads, or that they are bad. I'm just stating they are not the better choice of porters that know what they are doing. It is more desireable to have some 'meat' to work with, to port and shape as a good porter would prefer. For those that prefer not to remove a lot of material or would rather just do some touch up and go, then these are the heads for you. For some reason readers like to read into statements wording that is not there.Thanks Nab!
I had a feeling the later alum heads were better, just wasn't sure.