Best place for a narrowed rear end??

[laplander]

So now that the frame is C-notched, powdercoated and with the dropped spindles and coils installed, it's time to rethink the rearend situation. I was going to do like a few others I have seen and just run a monster backspacing to make an 18.5 wide tire fit with the expanded wheel tubs, but now am thinking I should just go ahead and bit the bullet and get a narrowed rear end. Anyone have any suggestions on where and what to buy? It's getting a 10.5:1 396 with Merlin oval heads and a 177 mini blower, so it's going to be getting abused.........