No they don't unless you are using an adapter plate then there is one. Note that i'm almost certain 308 TH350/TH400 crankshaft is different to 308 manual/trimatic/powerglide crankshaft to accommodate the torque converter snout. I've never really looked all that closely (I probably should) to see how much difference there is. This came up a while back, and it does show up in part numbers too.