Originally Posted by needturbo6
i know an engine builder, and hes built a few straight gas motors. both of which go very well. he said gas likes low duration and high lift (in comparison). gas also likes more lift and duration on the exhaust side than a petrol cam.
I've found the exact opposite. Gas likes low lift but long duration for the sole reason it needs to be sucked into the engine.... not pumped in. High lift but low duration tends to have nothing up high (my old cam was like that) where as the new cam put the gas system at its limit 1000RPM earlier that the old one! Dual pattern cams are good, they work perfectly well on petrol cars too.
The dizzy recurve costs SFA ($100-$150) and will make a huge difference over an unmodified dizzy. A cam is much more work.
As for which cam, I can't really suggest an exact cam until you know how much you want to spend. I'm a big fan of building the engine to suit a cam as the cam is most important part of your combo. Get it wrong and it'll never run right.
My combo (unfinished):
351C - 10.5:1 comp
Weiand x-cellerator intake
Pacemaker 4-1's into a dual 2 1/2" exhaust
Ported and polished 2V heads, dbl valve springs, RR's, etc
Custom Wade solid cam focusing on large duration and mild lift (very easy on the valve train too).
Ported impco 425 on a 700 Holley base with a 1" alloy spacer.
That combo currently makes 148rwkw@ 4300RPM. After that its lean, really, really lean. Pretty much, I need to get the LPG system replaced. It was also run with only 22 degrees total timing, with everything sorted i'm expecting to add at least 10 degrees more timing into it. The cam should run to just over 6200RPM so peak power should be up around the 190rwkw mark. With a larger cam and a dual GRA setup I can't see any reason why more power wouldn't be possible.... but its not cheap building an engine to that level.