I'm sure this has been covered before. I'm looking at options at this point. I am going to change out the rear end on my 51 Effie. It was born a 6 cyl. and has the original rear end which I think is a 411. the truck now has a V8 flattie with a C4 behind it. At 50 mph the thing is really revving and it sounds like it is giving me all it can. Just wanting to make it a little more interstate friendly and wondering what housing will bolt up to the springs without doing a lot of cut and paste work.