AJ's Opinion; Just for you 318 streeters
I'll throw on this quote "heads too". For whatever reason, folks don't like to put flowing heads on a 318. It's assumed the larger runners will kill velocity which will kill low end torque. I don't know of anyone that's bolted X heads on their 318 and lost performance.
This seems to be an issue often said by those that have not been there and done that. I threw 360 heads on my low compression 318 and gained performance at the strip. Even though the new ratio was 7.5-1 or lower. It went faster. Why? Head flow over compression every time is a winner. This has been proven many times over and even
@IQ52 has shown this.
Is it a great thing to do? Not really.
Is it a win, yes.
Would you have won more if you kept the compression the same or greater, absolutely!
The 340/360 head acts very much like a mildly ported 318 head. A mildly ported 340 head acts like a well ported 340 head, and so on up the scale. With this in mind, when does a head become to good for an engine?
That is a very good question and a bit hard to answer for any given size engine unless you are super specific on all the parts being used.
I think a good, but not definitive answer can be seen on engine masters (motortrend.com) where Freiburger tries to test this idea on a small block stroker (*I Think*) Ford between 3 different heads. The results may surprise you.
Here is another. The modern 5.7 HEMI. (What’s the actual CID of this engine? Anybody? My Brian is farting here!) The current head flows 300 (or so) cfm. But yet makes great power with Relatively low compression and a small cam size through exhaust manifolds.
THINK ABOUT YOUR COMBINATION !!!!
