Flathead flywheel

Is there any difference between the 59AB flywheel and the 8BA flywheel? Can I put a 8BA flywheel on a 59AB and visa versa?

Thanks,

Andy

 

You don't want to do that. The starter ring gear positioning is different between them.

 

And choice is determined by the block used...so a 59A with later crank still needs the early wheel.

 

This is the same issue I was asking a few months ago here is what I had to choose from.

Frenchy

 

Does this hold true for the French flathead, where the rear of the block is casted like that of the 59ab?? Trying to find out which flywheel to use with my French flathead, and have heard both 59ab, and 8ba flywheel to use. Oil pan will be 59ab.

 

The new compactstarters come in what they call aluminum flywheel model with different offset.
Its a solution to mixing them.

 

OK...I've never mixed them myself, because I've always had a usable proper combination handy, but I've heard from a number of people that a '32-48 wheel on an 8BA will lock up the engine through interference, probably at the plate covering pump drive. Other way, have not heard.
Ring gear position differs, and the dif is made up by the starter mounting. This is a significant problem, of course.
Usually mixing is attempted because the most common 8BA wheels are not easily usable with early Ford trans...is this the basis of your question? If so, last wheel shown has the even spaced bolt pattern and with '49-50 Merc pressure plate is good to go.
A few late ones are drilled for 10" plate, and so can be used by getting a '46-48 Ford PP. The 10" late plate, and also the common 9 1/2, have fingers too long to function properly in an early.
11" truck setup is another direct interchange to early trans use and will fit as is, but is heavy and stiff.
the 9 1/2 late used on most passenger cars either must be redrilled for 9 or 10 early, or a special rebuild can put right fingers into it.

 

Bruce is right on the money, as usual. My problem was not being able to tell them apart, thus I have 3 59ab flywheels (one pretty cool one that was lightened back in the day) that do me no good. Hard to find 8ba ones around here for some reason.

 

Easiest way to tell them apart from what I've been told is that on 8ba flywheels the pressure plate bolt holes go completely through the flywheel where as the holes for the pressure plate on the 59ab are blind holes.

 

If you continue to have trouble finding an 8BA flywheel, I have a 35 lb steel (not cast) one for sale.