[Bob Bidonde]

Two advantages of the clamp-on heater you depict are:
> It clamps to the exhaust manifold, so it is easily removable;
> I also act as a heat radiation shield plus it convects heat away from the distributor.

The nicest looking original period heater I have is painted Olive Green with red raised lettering. Original clamp-on type manifold heaters are common finds at swap meets.