flywheel question

[oldschoolbronc]

swapping my 1973 302w engine c4 auto trans out for a 1994 351w roller block,
will my original flex plate work with the 351w?

 

[thegreatjustino]

Your title says flywheel, but your post says flex plate.

The flywheel will work. All 351s were 28oz imbalance which coincides with the original 1973 302. Do you know for sure your Bronco has the original engine? Or at the very least a pre-1981 302? 1981 and later 302s were 50 ounce imbalance and those parts will not interchange with a 351.

Taking the imbalance I mentioned above into account, if you're still running the pre-81 302, a flex plate "should" work as well, but there are a lot more differences between the years, sizes, weights, and ring gear tooth counts than there are for a flywheel.

 

[DirtDonk]

In some old texts, a “flex plate” is another word for an automatic transmission flywheel.
Because automatic flywheels were, or became so lightweight, and therefore had very little “flywheel effect“ I think the morphing of names was appropriate.