Looking at the new AFR 210cc heads comp ported from AFR they advertise there flow numbers to be 311/237 with a 4.125 bore & 1-7/8th pipe!

Is there a way to find out how much the numbers are affected Without re-flowing the heads on a .030 bore and without the pipe?

Just curious I'm on the market for a set of heads and would like to get the actual numbers up front for the company that might possibly spec out my cam now rather then re-flowing them to get the exacts later. Thanks

 

There are smarter guys on here then me. But I think your trying to hard. These numbers are just a convenient way to compare the different heads on the AFR site. The numbers are not absolute and will be different on different benches.
What size is your engine going to be and what HP are you shooting for??

 

I was just using that as a example because there the only one's that post LT1 head flow numbers on a bore bigger then a .030

Im looking to make 600+ Flywheel Hp on a 0.30 396

 

.030 over, not .30

 

Many places that sell a LT1 version of a gen 1 head list the flow numbers from the big 400 bore which is what that is.

Some porters like to list LT1 heads at a 4.060 bore too, others do use a 4.030 because it is more realistic.

 

Engine masters recently had a great article on this subject.

Larger bore will flow more usually (app specific). Notice Chevy's trend with their bores....
LT1 4.0
LS1 3.905
LS2 4.03???
LS7 4.125
LS3 4.065
LS9 4.065

 

wow I forgot all about this thread. I thought thats what I put, At least my post says i did sorry.

Ok but im just curious I know flow numbers don't mean jack but if I purchased a set of heads for a gen 2 LT1 that flow 325cfm on a 4.060 bore how much would I lose or gain if I ran then on a 4.030 bore? Is there a rule or thumb to follow or anything??

Im asking for educational reasons, The company I plan to purchase my heads from has results and flow numbers on a .030 bore so I know what im getting.

 

I pretty much asked the same question on Speedtalk. Here is a link to the responses. I was kind of suprised.

http://www.speedtalk.com/forum/viewtopic.php?t=8676

 

Very good link, Thank you.