You'll want to look for a '67-'72 3/4 ton Chevy, V8 automatic. You'll want to look for the one with the drop out center section, GMCs and most Camper Specials use a different rearend (Spicer) that won't work.
As to the TH700R4 and 4L60E, both will bolt up to the 292 just fine, they are very similar to the TH350, I would advise the 700R4 over the 4L60E only because of the computor controls required to rune the latter. Those trannies are essentially the same otherwise. Yuo might be able to get away with just the overdrive trans swap, but doing both will give the best overall benifit, especially for a daily driver.
