Flexplate for 343 to TH400

[YooperCJ7]

I'm looking for a flexplate to run behind a 343 and mate up to a th400 trans. I looked around online and didn't have much luck. It was never a factory option so I'm not sure if anybody makes them or not.

[AMX69PHATTY]

Pilot Bushing hole in the back of the 343 crank is too small for a TH400.
I think there are bolt-in adpater kits available but includes a block to trans spacer ?
Is it a stock 343 ?
One way is to swap in a '72 & up 3.44 stroke 304/360 Crank.
Turns it into a 360 motor, and has 0.000 deck clearance nominal
if it has replacement aftermarket pistons that are .020 shorter than stock.
343's had .060 stock deck clearance. add .020 shorter piston, and the they're .080 down in the hole
and the 304/360 cranks have .080 more throw, or .160 more stroke, 3.44 vs. 3.28.
Would require a re-balance on the rotating assembly though.

Guess you could have a custom converter made with the much smaller pilot on
the front of the TH400 converter that would fit the 343 crank pilot.
Take a look at the hole in the crank and the pilot on the converter, there's a big difference.