300 Ford question

My shop truck project, mixing Ford parts, always dangerous.
So I am sticking a 300 into a 92 F250 where a 351 was, ZF tranny. I did all my research and it seemed all was fine. But then the correct holes were not in the flywheel for the 11" diaphram clutch. I had been told on Fordsix that all 300 flywheels were the same. NOT! According to parts books there is one part # up through 77 and another for 78-96.
Would any of you know what the differences might be in these 2 flywheels, other than holes?

I was going to drill it on a Bridgeport this morning if the clutch mounting holes are all that is different

I'm familliar with the small 6's but not the big 6's, so I didn't post anything, hoping sombody knew the answer to your question.. but I guess 6cyls are uncommon in a V8 world... anyway, I would ask Mike from Ford six performance parts/ Classic inlines, and he will know what you need, and most likely have the flywheel you need if yours can't just be redrilled.