Holley jets on 472

[kev472camaro]

I've just put a holley 750cfm double pumper on my standard '74 472 it starts and idles fine but wont rev above 3000rpm, i think the carb came from a small block motor so it could be under jetted, what size jets should i be using?

[68C15]

if you are not able to go above 3K in neutral it sounds like the main circuit is not working.
what jets, and power valve are in it now?
is fuel coming out the boosters any?

[Andy V]

somewhere around 72 jets on that 750 should be a decent place to start, with a stock motor.
65 power valve to start with, it may like a little higher one 75 or 85 too, you'd have to try it.

I'm running a 750 vacuum secondary on my 68' 472 w/ cam and head work. 72/76 jetting front/rear. 75 power valve.

[jtallman]

Incorrect jets or PV won't cause your problem;assuming you didn't change anything else I would suspect you are not getting enough throttle.Check throttle to see how far it moves;possibly carb blades are hanging on gasket or cable is not pulling carb lever far enough.Jimmy