Originally Posted by Lem Evans
I've dynoed two engines where both the 1 x 4 manifolds were backed to backed and both times the new/bigger manifold was better at and above 6,000 rpm. One was a 557" [4.440" x 4.50"] the other was 554" [4.530" x 4.300"].
A carb that will get to ~.5" hg would net a gain also.
you think one would be worth 15-20 hp on this engine?
my 565 with heads that flow 450 cfm at .750 was pulling only 1.3" vac with a 1,050 a few years back. It had the new/bigger intake. I'm thinking the ports on my old intake are a good part or the restriction with this engine.
off to a party.... see ya later