Mine didn't fit perfectly either, done the same way. Had to wap the rear floor pans a little with BFH. Jackstand the rear and front frame rails, If the doors latch smooth, get 'r done.
Doors have all way shut nice. I guess that would have been the first sign that i was doing damage to my car. and like i said before it's only a low 14 sec car with a real p.o.s. converter that get 2.2 sec. 60 foot time............... not a real torque monster/frame twister!
That's why I'm putting the frame connector on now. 340 is going away, and low rpm, high torque, 408 is going in.