What is the difference in size between the torque converter bolt pattern on the turbo 400 attached to the bread trucks and the standard turbo 400? I remember unbolting the turbo 400 from the engine when I got it and it had 6 bolts on the converter.(I live 3 hours from where I got the engine so I can't go back and look at it easily) a turbo 400 at my buddies house has only 3 bolt holes and they are the same size as the 700r4. I am thinking of using a chevy flexplate as a adapter bolting 3 holes to the ribbon and 3 holes to the 700r4. Now I have my ribbon slotted and am using washers to bolt up the 700r4 converter. It is still tight after about 1000 miles, but I have vibration similar to a bad universal joint at highway speed with the TC locked up. It makes me feel like with my bolt holes slotted it might be slightly off center??? causeing the vibes. Maybe the vibes are totally normal. I have no other street 4Bt vehicle nearby to ride in and compare to mine. I do know if I unlock the converter and drive the same speed the resonance goes away.