Rear End Questions...

O.k. I have a 8 1/4 rear end... Stock 3.23 or something?

I took it into a shop and they said they can add a sure grip/w 390 gears that they promised me it will hold up for about $1200.00.

I thought that was quite a bit of cash. I think I am running at about 400hp.
This rear end was originally behind a slant 6, and is holding up VERY well (so far) considering the 300 HP difference! I've roached the tires quite a few times, and it's holding up well.


I am however leery about the 8 1/4, and for $1200.00 I think may be better invested into a 8 3/4.


Could someone give me an opinion here, and perhaps if I go the 8 3/4 route advise me of parts I need and the money involved with this?


How hard does this rate on the "Do it yourself" scale? :)



Thanks much!!