i stuck with the 700 when i put the ls1 in my 89 camaro. wish i had changed to 4l60e, but its what i had. you would need to make a bracket to mount tv cable, if you want to do a nice job, then weld a bellhousing bolthole for the top. looking back, its not worth it, and i had to get a truck flexplate and spacer, and a mechanical to electric speedo adapter for my gauges. what computer are you using for the engine, or is it carbed? if you are going to do it, id go 4l80e. a stock one would hold up, and you could get a built one in the same price range you listed for 4l60e. the computer issue would be the same situation for either. if youre carbed, the tcm to control electronic trans will be 1000, so thats the only benefit of older trans. maybe a 400 and gear vendors?