Holley 4160 318LA Bog Under Load

also get the power valve correct before trying to tune the thing.
i put a 600 holley on my truck with a 318 (stock, 18" vacuum at idle), i put it to baseline (68 jets i think) and had to jet up to 72 before it stopped lean backfiring.
had to put an 8.5 power valve in it to get the part throttle transition working well.
i ended up jetting up again to 74, and the fuel mileage got much better.