If you are going to drive it, I would certainly put a TH70R4 under it: the shorter first gear and the overdrive fourth will be really nice, especially if you have (or install) the best rear end ratio to make it all work together. And a TH700R4 is pretty much invisible, so no one will know it is "modified"! ;-)
You could also build a 350 and dress it to look exactly like a stock 265, with the right paint, valve covers, manifolds, air cleaner...
But really, unless you are towing or often carrying heavy stuff, the 265 (with TH700R4) will be way enough!
Last edited by wave1957; 02/21/2011 1:58 AM.