Transmission Swap Questions 700r4 or 4spd?

[72step]

Man I haven't posted here in a while!
My truck has a hyped up 327, and hyped up TPI racing TH400 tranny. I don't use my truck a whole lot, and as a result, lately I've been having tranny fluid all over the floor under my truck. With all older auto chevy's I've had this has been a problem. This drivetrain has less than 5k miles. I'm thinking I should swap to a muncie 4speed. I actually have a friend who's dad has been wanting to make his 67 camaro auto, and has offered to trade his 4spd with scattershield, and hurst racing shifter for my auto. This swap would be the cheapest for me, all I would need is the clutch setup and linkages, and driveshaft mod.
I could go for a 700r4 swap, which would still take drive shaft and other mods, but that would run me well over 1000 bucks, and still is likely to leak when parked?
I'd really appreciate you all's thoughts and opinions on this. Thanks...