Gear choice

'69 dart
mild 360 magnum: 9:1, cam is 214/221, airgap and 650 eddy
26" rear tire
mix of city and highway driving

I have two rear ends to choose between, both 8.25: 3.21SG and 3.55SG.

On fence about what to pick.

Opinions?

i'm running a 3.23 with a 225/60-15 and want to go to a 2.76 or gear vendors but thats expensive. the 3.23 runs about 3k at 70 mph. i have a low gearst 904 and a good converter so i'm not worried about it not being peppy still. plus like @Kendog 170 said i basically putt putt around town so i don't need anything more gear.. i'm more focused on road trips these days..