Flex plate sizes?

How many different sizes of flex plates did the factory make for the 400's? The engine I just put in my 76 Cordoba is out of a 77 Newport, got underneath it last night to bolt the converter to the plate and it's at least 1/2" to 3/4" smaller. Not a big deal as I can just take the plate off of the original engine, but I honestly didn't even bother to check as I thought they'd be the same.

There are 2 different size flex plates.

I have a new one for a big block sale