Electronic ignition upgrade

[Tony Wheeler]

Originally Posted by colin jones

I think there was some talk about different length cam shafts for different distributors

Yes, the pre-42 camshaft had a longer nose to suit the diver's helmet dizzy. The post-42 camshaft had a short nose to suit the crab dizzy.

Aftermarket adapters were available to convert between the two types of dizzy, without having to change the camshaft. When converting a pre-42 motor to a crab dizzy, a spacer adapter was used. This fitted between the timing cover and the dizzy, moving the dizzy forward to accommodate the longer nose on the pre-42 camshaft.

When converting a post-42 motor to a diver's helmet dizzy, an extension adapter was fitted to the nose of the cam. This is the adapter seen above. In other words, it's a post-42 camshaft adapted to suit a diver's helmet dizzy.

Of course, it was also necessary to change the timing cover, because Ford changed the bolt pattern as well as the camshaft nose.

It's unclear to me why Ford made these changes. It would have been much simpler to design the crab dizzy to fit straight onto the pre-42 motor. It's as if they went out of their way to prevent interchangeability.