So my Christine, (Fury III, 318), has just been blessed with dual exhaust and glasspacks. Its just amazing. Anywho....it has been suggested that I will get better performance if I advance the timing a couple of points. Christine has original/stock parts on the engine. What benefits would I get, if any, from messing with the timing because I got dual exhaust?

 

I would try 8-10 Deg BTDC, no more because it is a heavy car

 

Timing is a "funny deal" for several reasons

First, because all these cars are getting old, and parts most probably have been worn or swapped along the way, you may not have the original distributor, or the one in there could have problems, broken advance spring(s) rust, etc sticking the advance, or a ruptured vacuum can or "all of the above." Also, worn distributor bushings affects the advance

Second, if it's not the original distributor, who knows!!!??? what the advance curve IS. Earlier cars had more performance oriented advance curves, 68, later, and 70 , later car had progressively worse advance curves because of Federal U.S. smog requirements.

Smogger dists tend to have very long, very slow advance curves.

So you have your work cut out for you.

You have "what is initial" "how much mechanical" and "does the vacuum work?"

You need to degree the balancer, mark it somehow, buy timing tape, or use a "dial back" (delay) timing light which displays advance.

In addition, it's a good idea to use a piston stop to establish that the timing marks are actually correct, before you start.

So,

INITIAL............

With the engine completely warmed up, and the carb idle mixture adjusted, use a tach and or vacuum gauge to establish maximum idle speed and or vacuum. Sometimes you want to retard it from this point a couple of inches of Hg.

This might end up being 10, 15 degrees BTC. So long as the engine does not ping under heavy load when warm, and low/ med RPM, and so long as the starter does not "kick" on starting, you should be OK.

MECHANICAL. This is where the marked balancer or delay timing light comes in. You want the mechanical when "fully in" at high RPM to be somewhere around 34--38*, again, no ping under heavy throttle when warm.

You may have to have the dist. recurved or buy a performance distributor, or you might be able to "jiggle" the total figure above, and accept a lesser idle/ initial figure, maybe back it down, say to 8 in order to keep the mechanical from over-advaincing (out of the sky example.)

Last you have

VACUUM which only works at light throttle, cruise, med to high RPM. This adds another few degrees on top of the mechanical, and can be over 55* BTC on some cars, that is total adding initial + mechanical + vacuum

 

Thank you folks for your response. 444R, thanks you for your detailed response. I appreciate the time it took. I will take that info and make sure my mechanic takes your advise under consideration.