The Stovebolt Site Forums The Shop Area Engine Shop What engine and what vac. advance?

On 47-55 truck engine the vacuum advance is parallel to the block; the automobile/passenger engines the vacuum advance is at an angle to the block.

The odd thing is that most Truck Shop Manuals show the automobile vacuum advance unit.

Here are both units next to each other.

If you have the correct base/clamp, this one will work , after drilling out the pivot post and using the original pivot screw.

Tim