Is it possible to put a crab dizzy on a 51? I have the crab dizzy and timing cover. Need a mechanical advance unit for my twin 97 set up and I have these parts.
Yes, but you will have to change out the cam. Easiest solution would be to install one of GMCbubba's units, a converted gm distributor or change to an electronic unit like MSD.
There was a thread on the "Ford Barn" about this recently. I think they showed a way to do it without changing the cam by cutting the gear off the later cam and machining a slot in it. I like the serviceability of post distributors, so I just skimmed the thread. I think that was the jist of it, though.
I'd message GMC_Bubba or go to his website.. http://www.bubbasignition.com/ He is the dizzy master...
If it's done right: you will need to change the cam to early pre:49. You will also need to change the timing gear set to early pre:49. On 32-48 engines the cam thrust pushes towards the block. On 49-53 the cam thrust is towards timing cover. So you will need a early cam and timing cover plus early timing gear set.