differential questions new

[rer_239]

i'm back! bought a rear axle (cheap) had to replace the axle shafts and housings. found better housings and shafts. my first axle had a 37 tooth ring and a 9 tooth pinion gear. the better shafts came assembled with the carrier assy and spider gears. but it had a 34 tooth ring gear. can i use just the better axle shafts? according to Tom Endy both 34 and 37 ring gears used a 9 tooth pinion gear. does that mean that the 9 tooth pinion gear will work on either ring gear. i planned on using 16" wheels on a stock chassis/drive train and wanted to end up with a car capable of 50 mph with out overenxtending the engine (approx 2000 rpm). the 37/9 combination w/16" wheels (i think) ends up with 2400 rpm @ 50 mph. the 34/9 combination would lower rpms to approx 2200 rpm.
first question can i use just the better axle shafts
second question will both ring gears (37 and 34 tooth) work with the 9 tooth pinion gear.
whew, sorry about the rambling.