I am doing a swap mating a 453 Detroit to a M5R2 transmission. I need a zero balance flywheel to bolt to my flywheel adaptor. The adaptor accepts any small blk ford flywheel.The engine is internally balanced so I heard I need the I6 flywheel to work with my 10.5" clutch and pressure plate. I bought a flywheel for a 78 ford f150(EOTZ-6375A) thinking it was right but it turned out to be 11" and 10mm bolt holes. I need 7/16 holes. Can anyone tell me which flywheel will work? Thx in advance.
Lee .

 

Perhaps a later model 300 flywheel will have the right hole spacing for the clutch, assuming the clutch is a standard clutch for a M5OD trans. What did the clutch come from?

I know of no other engine that has a small block crank bolt pattern, and is neutral balanced. As far as I am aware, all small block V8's were externally balanced, while the I6 is internally balanced.

7/16" holes are quite large. I doubt you will find any "stock" 300 flywheel with that large of holes. As such, you may have to get the flywheel custom drilled.......

 

The clutch is from a 91 mustang with a T5 / 5L combo. When I google flywheel bolts for an early ford it comes up 7/16 -20 X 1" (for manual). My adaptor is threaded 7/16 -20.

 

Ok, I misunderstood on the bolts. I thought you were still talking about the clutch itself, not the flywheel mounting bolts. This had me really confused, as I've not seen any clutch cover bolts that were larger than 3/8" used in automotive/light truck applications.
If that flywheel was made in china, it could be drilled wrong, as the 300 should use the same size flywheel mounting bolts as a small block V8. Wouldn't be the first time they got something wrong......
Unless you bought the flywheel at a ford dealer, it was likely made in china.

You will likely need to use a pickup clutch, rather than the car clutch. Cars used some odd sizes for clutches, while trucks tended to have a run of the mill 10" or 11".

 

Thanks for the replies RW,
When I looked up the part # for this flywheel it not only fits the 78 truck but also up in to the 90's.and v6's. That makes me think that is why it is metric, and now I am questioning weather it is zero balance? I can't post a pic of it, I suppose my post count is too low.
I would like to use my new 10.5" Spec clutch and PP but if I have to by a 11" kit I will. I just thought I could buy a old school flywheel of a I6 with 7/16 holes for the crank/fw that would be internal balance.