This B&M adjustable vacuum modulator lets you adjust your shift points within a range of 2-4 mph.
Supplied adjusted for normal shift points.

Fits all General Motors TH350 & TH400 tarnsmissions

With a gold cadmium finish and an O-ring seal to stop leaks, it looks as good as it works !

Note: If your motor does not make adequate vacuum, you will not be able to make the stock or B&M modulator work properly usually resulting in late, shifts.