what we did with mine was they put a th350 an they put a spacer 6 inches on the th350 couse it was shorter ,?does track only meen oldshcool your going ,with mine thats all that had to be done other then kick downcable ,my shifter stock works fine,but I also have carberated 406 in it now, I think the flex plate is different was for mine too ,then again I did not know you could put th400 in with lt1 engine, i like 3 speeds ,an the trannys cost big cost difference th400 can be had new for 1000.00 an the stock one cost a lot more new or rebuilt,an I have to agree with the guy who builds trannys ,how does th400 go in a 95 camaro without changing the engine like I did ,so unless your going back to old school with the engine ,I don't see how it works ,as you can see its simple after an engine swap like mine

 

You will need a new crossmember and depending on what size tailshaft a new driveshaft also I had to have a special u joint and new dipstick tube

 

stock cross member worked fine for me ,like said 6 inch extention also work fine with stock drive shaft any trans guys should know that,if your staing with lt1 engine then you should talk to transmission shop