Originally Posted by b00tz
almost forgot this too : i have the idle set to around 1200 , i have to fiddle with the screw alot sometimes it idles there and sometimes it decides to idle higher.
once in a while it backfires out the carb and it catches on fire :/
and when i shut it off she keeps rolling on a little bit dieseling. i dont think the butterflys are open too far but i may be wrong
So after all this where are we today then, how is the idle now?
Do you have a bogger you call a road truck or a road truck you call a bogger? You could lock the timing at 38 and do your WOT mud pulls and call it a day if its a competition truck.
If you have dual purpose truck then power time it to 38 Deg BTDC @ 4000RPM. Go to idle, adjust idle/carb mixture for max vacuum. Note the base timing, add vacuum advance to manifold vac, re adjust carb. How much vacuum advance?
If vacuum adv is adding more than 12 deg timing then limit it with the street fire vacuum adv limiter if you have that kit or get the crane limiter plate.
dont exceed 50 deg total timing advance
If you have 18 base timing and then add the 12 deg vacuum adv at idle you should be sitting pretty with 30 deg at a 900 idle as long as there is enough hg" vacuum to pull in the vacuum can. As the revs come up the mechanical adv will add advance as the vacuum adv drops out, I dont see many boggers idling at any less than 900 with a 4 spd so 1 stiff curve spring in there to avoid adding mech adv at idle, then change the other spring heavy/lite to get the curve right,,,all in by Xperimentation RPM