Which flexplate for C4 behind 351?

[rpm4lalo]

I have a 69 fatsback which now has a mid 80's 351, the flexplate it came with was too large in diameter to fit in my C4's behousing, so I use a 81 and up 302 flexplate and almost everything bolted up correctly. one problem, the TC studs are sticking too far past the flexplate creating a clearance problem.

The weights are different, but I can alwasy get it rebalanced but the offset on the flwheel is not he same causing the clerance problem, if I go to my local parts store what year and car should I specify in order to get the right flexplate for my setup?

 

[D.Hearne]

You need a 28 oz/in balance 157 tooth flexplate. The one you have now is a 50 oz/in. All 351 W & C's used the 28 oz/in balance. You can spec a 289-302 flexplate for any small to mid size car,up to around 1979, those will should have had the smaller 157 tooth flex with a 28 oz/in balance. The switch to the 50 oz version happened sometime between 80-82.