tnt76vette

Since I hadnt done so in awhile, I hooked up my V gauge today to check things out. Was pulling 14" at idle. Adjusted the timing for best possible vacuum and got it to 15 1/2. Tightened the distributor down and took it out First time I floored it I got rubber from 1st to 2nd (350 Auto)! Never happened before! No timing lite was used in this "Tune Up", just a cheap Vacuum Gauge. I'm just passin' this on for info...... :D

bigvette1

Interesting to find out what advance at idle you ended up with at 15 1/2"?

tnt76vette

I'm really more of a "seat of the pants " Guy, than a timing numbers tuner I guess, so I really cant answer your Q. Am sure that many seasoned veterans of the Motor World know about this tip, I was just passing it on to others that didn't, like me, till today............. :cheers:

Kevin Mason

any drawbacks to this tuning method?

1979toy

Yes there are. If your distrubitor is advancing 20 degrees with the mechanical advance and your vacuum set timing was at 22 degrees then you would have a total timing of 20 + 22 = 42 degrees. This asumes that your advance was in the full retracted position at idle. The small block Chevy likes no more than 36 degrees of total mechanical advance so you would be hurting the engine at higher RPM's.
But the truth is - a lot of people have tuned this way for years and been happy with the results.