Tuning advise for 360

bbeep71 said
It idles at 10"vac in gear. Powervalve is stock 6.5"

As it sits, it would need a 5" powervalve. Rule of thumb is cut the idle in gear vacuum in half and that's your PV number. That's straight from the Holley tuning guide. The 5 PV will lean it out some too. 72's really don't seem that rich for your combo and shouldn't be blackening the plugs that bad. Be sure to check your float levels too.

Locomotion said
Besides getting the power valve right, make sure that the primnary blades aren't open too far. Slightly open the rear secondary blades a bit using the adj. screw in the baseplate under the secondary vacuum pod. Then redjust the idle screw on the primaries.

Agreed. Do this after setting your timing to what cracked suggested. The primary throttle plates should not be more than just a hair into the transfer slots.

Set the idle mixture screws to the best idle in neutral, then turn them out another 1/4-1/2 turn. That should help give the smoothest, cleanest idle in-gear.

Make sure the float level is correct as well as the timing.

Beat me to the float level adj. I see, lol.

crackedback said
16-20 initial? It's going to need a bunch more than stock specs call for.

Timing first, carb adjustments second.

Cracked is right on here. Timing first, then the carb adjustments as timing will effect primary throttle plate opening and idle mixture settings. If you're using a MP distributor, you can limit your mechanical advance via 2 Torx head screws. This will allow you to bump your initial timing without going over your total timing spec.

For instance, I set my MP distributor to allow 9 distributor degrees on the bench, which is 18 at the crank. I then installed it at 16 BTDC which gives me 34 degrees total. This can be done on a bench without a distributor machine and I plan on doing a write-up soon as I already took the pictures. :read2: