What size jets should I run?

[ed1le]

I just picked up a 600 double pumper for my 355. The 355 is a mild build, 9 to 1 with small valves, RPM intake and the cam is in the .450-.460" lift and 272-278 duration range (don't remember exact specs & lost the cam card). Right now the carb has 74 primary jets and 76 secondaries which I'm thinking will be a little much for this set up right now.

[JeffT]

Look up the model of your carb on Holly's website and find out what it came with out of the box. Start there.

[Shawn MacAnanny]

My holley 750 came with 72 primaries 76 secondaries. This setup was just about perfet for my 346 but its pushing about 550hp.

I think you should run something like a 72 primary and a 74 secondary or so