Racers don't use vacuum advance because they don't drive part throttle. My 440 runs way better part throttle with vac advance. Your initial timing is too much imo.
This is what I run in the 440 -
http://www.moparaction.com/Tech/quest/SLOW_CURVE.htmlTech Question
bob santarsieri, schaumburg, IL, 71 plymouth road runner 440
I have a msd pro billet distributor and msd 6al box. What would be the best setting for the distributor? Right now it is set at 2 heavy silver springs and silver bushing per the instructions. It starts to advance at 1400 and goes to 5500rpm then levels off. What would you suggest. 440ci, 0.040" overbore, 0.474" purple shaft cam, Hedman headers and 3.23 gears. Just street driven. Thanks for your help.
Bob, assuming sufficient octane vs. C.R., you need a curve something close to this:
Under 1400RPM - no advance - set initial at 15 degrees BTDC
2000 - 10 dergees mech (25 total)
2500 - 20 degrees mech (35 total) - all in.
Plus, at LEAST 15 degrees of vacuum advance under light throttle (50 deg. total, 52-55 better).
If it currently doesn't go to full advance until 5500, you're giving up lots of power.
If it currently has less (or no) vacuum advance), you're giving up LOTS of fuel economy and fouling plugs.
Rick
