What should I do?!

So my beloved '64 Dart has me in a predicament. I bought the car off of Craigslist a few years ago for $500. It was intended to be a temporary fix for my vintage Mopar cravings. Well I ended up falling in love with the old heap. I've since replaced the old wore out 170ci with a low mile 170ci out of an old lady owned Valiant, the three on the tree has been replaced with a 4spd OD, and the rear was replaced with a 8.25 rear end with 3.55 gears and a SureGrip. The suspension has all been done also. Front end rebuild kit, 1.03" Tbars, front 11.25" disk conversion from PST, Hellwig sway bars, Espo leaf springs and KYB shocks. It used as a daily driver off and on.

The good is that it gets stupid good gas mileage and is as docile as a sleeping paraplegic kitten.

The bad is that the old girl is slooooooooooooooooow! And the gear spacing in the OD trans is absolutely horrible for anything resembling spirited driving!

So do I swap in the warmed over 360 I've got on the bench?

Or should I just do some mild power mods to the little 170 and hope for acceleration?

Either way I think I'm gonna go with a close ratio 4spd instead of the OD. All my driving is in town or backroads anyway.