I know this question is more of an experimental process, but here goes. I have an Edelbrock 1901 Quadrajet on my 1970 402. It's calibrated out of the box and it definitely needs some tuning. I just went through the motor and I'd like to get the carb dialed in as best I can before I fire up the motor. Here are the specs -- CTW 402/350hp, .030 over, 10.25-1 compression, Comp 280H camshaft installed 4 deg advanced, Performer RPM manifold, MSD ignition. Stock small-valve closed chamber oval port heads, 3-angle valve job. Hooker Competition headers, 2" primaries, 3" collectors, 2.5" flowmaster exhaust. 3.31 rear. TCI break-a-way converter, T400. I hope I didn't forget anything. Another question -- should I be running the stock plugs -- R44XLS -- or is there a better heat range? Can you even estimate this without trial-and-error testing? Thanks!

The 1901 carb is jetted at 069 primary with 36 B rods and secondary DR rods. This is a little on the lean side, but maybe not too bad with your MSD spark. I would suggest going with 72 jets and 39b rods which should maintain the cruising A/F ratio with a little more fuel at half throttle. I don't know the actual size of the DR rods but you would probably need around a BA rod with a tip of .055 inch. Like you say it's a matter of playing around with it. The R44XLS plugs should be pretty close and the X (I think) is for an electronic ignition with a wider gap as needed. Sounds like a potent setup although I don't think I would have advanced the cam, but that's just my shadetree opinion. Good luck with this. tom

Toms right. My expereince was that street mod motors responded well to 72 jets and 37 rods. As for secondaries, I dunno.