[Formulajones]

I run my 70 (original carb) off full manifold vacuum, bypassing the TCS setup that originally only supplied vacuum to the distributor in 3rd gear. Now with vacuum all the time it does better on gas around town in stop and go traffic and runs a little cooler as you would expect when the engine gets a little more part throttle and idle timing, it's just happier.

This would not work well however if you have a vacuum advance that adds a ridiculous amount of timing, some as much as 20 degrees, would not work in this situation if you have any decent amount of curve in the distributor.

So I've modified the vacuum advance to only provide about 12 degrees of timing when it's at full vacuum. This gives me great drivability, mileage, good stable idle with more idle vacuum, just an all around happier engine.

Up to you, just something you have to experiment with and spend some time dialing in.