Technical Question re 8BA flywheel interchange

Hello! I feel like this question has probably been answered on the forum already, but I searched and couldn't find it.

I recently acquired two 8BA Ford flathead engines. One is from a pickup truck and was locked up solid. After a bit of struggle, it is disassembled and at the machine shop awaiting inspection. It has a 10" clutch with the corresponding flywheel and pressure plate.

The second engine is from a heavy truck and is an older Sears/Allstate rebuild. It turns over, has minimal cylinder bore wear, a tight bottom end, little oil sludge, and no visible cracks to my amateur inspection. I would like to see if I can get it running without tearing it down further for a full rebuild. It has an 11" clutch with the corresponding flywheel and pressure plate.

The second engine lacks a bellhousing and starter plate but does have a working starter motor. When I bolt on the bellhousing and starter plate from the first engine and use the starter from the second engine, it cranks, but with some noisy interference. I am presuming that this is due to differences in flywheel diameter and/or ring gear.

My question is whether I can use the flywheel/clutch/pressure plate from the first (light truck) engine to replace the same components on the second (heavy truck) engine. Will they physically bolt up? Is balance affected?

The car that this will power is a fiberglass special, so the loss of the 11" clutch is probably a good thing.

Can anyone point me in the right direction on this? Thank you in advance for anything that you can share.

Barry

 

I don’t see where that would be an issue but then I don’t know flatheads like the back of my hand either. If it’s anything like a small block you would need the harmonic balancer off the other motor to match the flywheel/clutch assembly?!?

 

If you truly have both flywheels from 8BA style engines, they should be the exact same dimensions. See if they both have the pressure plate holes drilled all the way through. That’s a clue on the stock Ford late flywheels.

If by chance you are using an earlier flywheel on the later engine, it won’t work right.

All flathead flywheels of any year should be zero balanced. Not dependent on the engine for balance.

 

Thanks! I am heading up to my engine rebuilders tomorrow to reclaim the light truck flywheel and I will check.