OK, here we go. I pulled my 340 to put new rod bearings in and replace the oil pump. I installed TTI headers and a new mini starter and also put my old old convertor back in. I had a TCI in it and switched to a TA and now back to the TCI. I had alot of trouble getting the bolt through the trans mount and getting the cross member to line up when re-installing the transmission. Now, I have a terrible shake and it rattles and pulses even through the dashboard. I have replaced both U-joints and still no improvement. So, now what? Is it possible for the convertor to be doing it even though it wasn't there before? Should I just pull the tranny and swap the convertors back out (which I would rather have the TA back in, but not a biggie)?

Just a wild guess here but if the tranny mount lined up befor it should now. Is it possible that you installed the engine cocked in the k member. try to loosen the engine mount bolts and the tranny mount bolts to see if it will center itself up.

I'd bet the shake/vibration is in the mount or crossmember.

Is this really possible? If so, it will save me from pulling the transmission out completely.

crack flex plate come to mind! but you would notices it when you driving!

Yeah and I didn't mention it's a '73 and has the big flex plate from B&M.

after R&R ing the TC what changed the length of the eng/trans so that the trans mount wouldn't line up? did the eng shift back(or forward) a bit & is the trans bolted to the mt/xmember correct now? I would think that the wrong TC(balance wise)is in there now.

you don't think maybe a weight fell off? 340 and 360 are balance alike ain't they?

Did the tranny seat completely? Since it is a 73 it should have the cast crank and is externally balanced. Any chance the weights on the TC came off? Are the TC bolts all tight?

It's a neutral convertor and I have the flex plate for the external engines. I have used this combo before with no problems. I had the trans rebuilt and installed the TA convertor when it was out. I have decided against racing the car as much as I was and when I pulled the engine the last time to put bearings in, I also put the TCI back in and now have the vibration. But now I am left to wonder is it a coincedence or is something else to blame. Also, when the engine was out I replace the rubber spool type mounts for the engine. I don't think that should matter much though.