When I swap from an auto tranny to manual, what do I do with the vacuum advance on my distributor? Do I plug it? Then do I need to recurve the distributor in some way? Just curious and this popped into my head, thanks.

I just did this, and at the advice of the shop that did my motor, I had them re-curve the HEI unit I was running, and at the same time we eliminated the vacuum advance (I have the port plugged off on the HEI unit and carb). Seems like some people swear by using the vacuum advance, others like to just use mechanical advance, not really sure if one way is better than the other..I guess it depends somewhat on what your setup is.

I've had 3 experiances with vac advance. The first was on a 305 engine in my old '67 1/2 ton. Notibaly better throttle response and milage with the vac advance on. Same with the 350 in my old s10, both with automatics.... and my dad's '72 Maro with a 350, holly 650DP, it liked the advance also.

Just my .02. If you're racing all the time, it's not needed, but if you drive on the street alot it helps milage too. Specially on the freeway.

If you drive at part throttle...you need vacuum advance.

Sorry guys, had a brain fart when I posted this, and thought that the tranny was related to vacuum advance...but I guess it does go from the carb to HEI. graemlins/clonk.gif Don't know why I thought it had anything to do with trannies...that's another vacuum all together. Anyway, thanks all.