Originally Posted by MikeB (Post 7469718)

If it's a used carb, I'd determine which jets, rods, and springs it currently has. And then go from there using the excellent user manual. Altitude, engine vacuum, coolant temp, and exhaust efficiency will affect your final settings.

Also, are you sure it's a 650? That would be their Thunder AVS series. The 1406 that you mentioned earlier has a totally different jetting chart.

Originally Posted by rich weyand (Post 7470007)

The two characteristics of a vacuum advance canister that matter are 1) total advance and 2) vacuum required for total advance.

The vacuum advance cans on emissions-era distributors are usually too much total advance. The cans used on aftermarket distributors usually come in too early (with too little vacuum) for the SBCs in our trucks, which run higher vacuum than "high-performance" engines.

The AR23/VC1853 is right for non-emissions low-compression SBCs, with 7.5 camshaft degrees (15 crankshaft degrees) at 12" of vacuum. Most cans have more advance than that, and kick in at a lower vacuum level.

Originally Posted by rich weyand (Post 7472580)

The AR23/VC1853 vacuum canister on a stock HEI distributor is the way to go for a non-emissions crate engine.

Originally Posted by chiro22 (Post 7472815)

really appreciate all of your help. Do you have any opinion on swapping out the 350 for a diesel?