Had same problem. Converter hub was bottoming/ballooning out on crank. I put .025 shim between crank and flexplate and .025 shims between flexplate pads and converter. You want as much clearance as possible between converter hub and the crank. With engine out of the car I bolted the converter up with flexplate on and used clay to determine clearance between converter hub and the crank. You could also use a small wad of aluminum foil to determine clearance. Without the shims it had ZERO clearance. Solved my problem...hope this helps..