55* total timing? WTH?

67Dart273 said
x3

BUT THAT IS NOT what he said

If he has 15 initial and 24 mechanical this is THIRTY NINE total under power. Way too much most of the time. If he backs the total (without vacuum) back to 35 or so, the initial AND the total with vacuum is going to go all to 'ell

What you want

Set the initial for "all it will take." This means tune for max idle RPM and vacuum, if necessary you can back this off a bit. "The test" is kicking back on the starter, and low speed ping.

Then you need to figure out what best / safe power is with no vacuum. This is your 35 or so, plus or minus. THE DIFFERENCE BETWEEN THESE TWO is what you need to curve the distributor mechanical for. IE 18--20 or whatever.

THEN you add the vacuum on the end, and this can be 'quite a bit' as the vacuum is only under cruise and light throttle. 55--approaching 60 is not uncommon on "fuel mileage" vehicles

AbodyJoe posted this years ago:

http://www.forabodiesonly.com/mopar/showthread.php?t=158842

^^^ Exactly this. You don't add up all 3 numbers because at WOT the vaccum advance is not in; there is very little vacuum at WOT, ported or manifold. The only time you have them adding up is at higher speeds with light cruise; in that case, the fairly closed throttle will allow ported vacuum to build, mechanical will be all in or nearly all in, and you will get a lot of total advacne.