I had a factory 16:1 manual box in my 66 Barracuda with a 340. It was a bit tough to park. Once you were moving, it wasn't too bad. But with a big block AND fast ratio arms with those tires? Good luck, unless you are REALLY strong.

Don't try a 24:1 box for handling. You will be disappointed. They are about 4.5 turns lock to lock and just way too slow for a handling car. I tried it.