Found 8 1/4" Rear End

[68DartProject]

I found a 8.25 rear end with 245 gear ratio. I was looking at some tech info from some ring and pinion builders. They are saying anything above 271 that I would need to go to a 271 housing before I can go to any lower of a gear.
The rear end came from a 73-74 Duster. I am wanting to put 355's in.
Questions:
1. Was there a clearnce problem?
2. And are all the 8.25 the same?
3. Will I just need a complete rebuild kit with gears I want?
4. What are the steps?
5. And where can I get a master kit?
6. Or do I need to find a 271 housing before I start?

Just some question I have before I get to far ahead of myself.

 

[pettybludart]

I just loade a 8 1/4 rear in my trailer with 4.10 sure-grip,Richmond gears have 100 miles on them.Hmmmm maybe I should pull the centerpiece out and sell$$?This is outta my 73 Dart Sport 340.

 

[slantysix]

Mr. Pettyblue...are you around tomorrow afternoon??? Did you say you found another 8 1/4 axle??? Is this the same one from before or is it another one with two axles???

 

[grumpuscreature]

The 2.45 ratio used a different carrier to make up for the pinion head diameter. To swap in 3.55s you will need a carrier from a 2.76 or lower gear set. Any A, B, C, E, F, J, M, truck/van 8 1/4" with 2.76 or lower gears will get you the parts you need to swap 3.55s into your housing. The axle spline count changed in the mid to late 80s. Avoid the ones with the ABS sensor in the housing and you should come out OK. Or you could just get a new differential carrier. Mancini Racing, Dr. Diff, and Randy's Ring and Pinion are good sources for parts. Hope this helps.