Need a flexplate

I got a power master for early pre 1988 700r4. I have a Advance Adapters kit on the 360. My dad had this done to the car some years ago before I got it.I had forgotten all about it until back in March when I started chasing a drive train vibration. I found 1 of the 3 torque converter to flex plate bolts busted off. But with what happened to you I will compare the new starter gear to the old gear. Thanks for your response. I joined a face book 68-70 and 71-74 Javelin & AMX group a few days back and they were talking about this company Showcars that has AMX/Javelin parts, just so happens they list a flex plate for 343 & 360 v8 for under $50. http://www.showcars-bodyparts.com/amxjavelin.html.

As with any and all things, including vendors, a little research is due diligence...

Years ago I bought a billet machined steel flex plate from an outfit in Atascadero ca (when I still lived there) the car was eating the stock ones... anyway, it’s a 401, and the plate is heavy and requires a spacer between the bell housing and the block... I’m I loosing performance by running the heavier plate?

If the car is eating flexplates there is likely something wrong with alignment somewhere. Either the engine is incorrectly aligned to the transmission, or flexplate to the crankshaft. As per factory design all this is carefully done with a flexplate pilot on the crank and dowels to align the transmission. Sometimes with modifications or changed parts the careful factory design gets messed with. Aftermarket stuff rarely has the same level of engineering a factory part has, so if something has been changed somewhere look very carefully. I've seen disasters like someone hand grinding out a pilot of early flywheel to fit a late crank.

Hey Ken,  care to share how you established proper alignment? Also assuming I have proper alignment what would the disadvantages of running the billet be?