If you can find the right electronics package, the 4L80 transmission would be a lot wiser choice. We've got one behind a 454 in a 35 foot motorhome, and I'm constantly amazed at how bulletproof it is!
The 700R4 got a name change to the 4L60 to avoid all the bad press the early ones got. Back when I was building a bunch of those early units, the fix was to put the "Corvette" overdrive clutch assembly in them, the one with the deeper clutch drum and more clutch discs. Toggling in and out of overdrive was the problem, resulting in overheating and slippage. The biggest fluid cooler you can find is a must, and stay FAR away from any shift kit type modifications. The throttle pressure adjustment is critical, and monkeying around with the factory shift sequence is an exercise in frustration.
Jerry