drewkins
Well-Known Member
Looking to build my 318 to around 400hp. I was wondering if anyone had input on the Edelbrock vs Indy lax imm heads.
Thanks
Thanks
It's a common misconception that 360-340 heads work good on a 318 street car.
The engine won't produce good power until the upper RPM's.
Since a 340/360 head has the larger ports, it acts like a ported 318 head but with a lower velocity. Your better off selecting a good 318 head to port for a higher velocity which will equate to a snappier throttle response and a higher quality air and fuel charge.
It is the COMBINATION of bore, stroke, cam choice, intake manifold, cylinder heads
Odd, that sounds like what I said... and a B.S. (Barbra Streisand) wasn't really necessary.
Exactly! Bigger motor (CID) needs bigger ports and more CFM to work right OR you have to generate more air flow (A.K.A. more RPM) to get results. The trade off with bigger ports and low CID is weak bottom end because the air loses velocity (slows down) trying to fill the runner volume. 318-360 performer manifold it what that manifold was made to do. 318 ports and runners for a 360 huge low end response, high velocity for a smog burner engine better bottom end torque, snappier throttle, etc.
Again I come back to the small CID 383 using B1 heads comparison. Real life case in point. 500CID BBM 2.19 int Eddy RPM heads 6.86 1/8th mile. 451 same everything conv, trans, gear, etc. With one exception: went from 1.6 rockers to 1.5. Same everything, cam and all. 6.80 with less cubes. The heads were the limiting factor for the 500" motor. But the 451" had the better combination so it worked better.