What rear end gears for 904?

3.55 is good all around gear for highway cruising and "decent" street pick-up.
My DD has a 3.21 with an A999 transmission, most likely with different 1st, 2nd gear ratios than yours. (2.74, 1.54 vs. 2.45, 1.45).
My rear tires are only 26 inches (245/60R15) diameter. I can squeak the tires off the line and she does have decent off the line acceleration, but she is not a 1/4 mile blaster.
I can do 70-72 mph and be right at or just below 3000 rpm. The A999 has been modified with non-lockup mod & TA Cheetah Valve body.
I do a few trips from UT to CO and back each year (1,000 mile round trip) with no issues. 15.5-17+ mpg (depending on how bad the WY cross winds are).
That said...
I'm currently rebuilding an A500 out of a 92 2wd Dakota, which is a project because it involves some fabrication mod of the transmission crossmember and tunnel area.
Once done the rear gears are going to change. likely to either 3.90 or 4.11.
My 360 is no slouch either but it was a budget build with Ebay specials and hand me down used parts. (
1990 Roller cam with low miles.
Lunati Voodoo: 270/279 dur. gross valve lift .515/.530 (Going 1 step bigger soon)
Speed-Pro flat topped pistons .020 below deck.
Weiand action+ intake (Going Eddy Air-gap soon)
Ported 340 2.02 valve J-heads for now, (not the best but hey they were cheap and already ported).
Street Demon 750.
MSD 6A CDI system.
Hooker Comp Headers (free, was in the trunk when I bought her)