i just got the go ahead from my wife to order a moser 12 bolt for my 67.
im concerned with gear choices.
if im going to blow $1900 i want to be sure im happy with my selection.
i was thinking about 373's .
my combo is aprox. 400 horse 350 with a turbo 350 tranny , 2200 stall.
im running 245-60-15's out back.
how would i figure out my rpm's at high way speed, i dont want it screaming for mercey at 60.
its main use will be local crusing with an occasional trip to the track( im looking for mid to low 12's)
any opinions or past experences would be greatly appriated
thanks, joe

Richmondgear.com has an excellent calculator, you supply the axle ratio, final trans ratio (1 for th-350), tire height, and mph.

Example: for 65 mph, trans ratio 1, and 26" tire:
3:73 axle = 3133 rpm
3:55 axle = 2982 rpm
3:36 axle = 2822 rpm
3:08 axle = 2587 rpm.

If you had an overdrive transmission, the rpms would drop quite a bit due to the final trans ratio (.70 or .67 etc)

Here is something that might help. http://www.windyhollowdragway.com/horsepower2.htm

here's classic chevy 5 speeds calculator: http://www.classicchevy5speed.com/RPM_calculator.swf
While you're there, shop for a tko!
Unfortunately, anything you do with a stock 60's trans will be a compromise. IMHO, even my 3.08 rear was screaming down the highway with a 1:1 high, the tko gave me the best of both worlds, first is like a muncie with 4:11's, and 70 mph = 2000 rpm in high. A four speed overdrive automatic will give the same effect, a lower first and a higher high.

I was running a near identical set with a TH350 a few years back. I finally got sick hearing the engine turn 3200rpm on the highway. So I switched to a 200-4R, and I'm much happier now.

65mph + 27.5" tall tires + 350th + 3.73's = 3000rpm in my car (include converter slip)

With a shorter tire (26.5") you're going to see higher rpms (3300ish????? @ 65).

Still very good all around gear IMO. :D

well it looks like for my intended driving 373's might just fit the bill.
this should work out pretty close to what im looking for.
i might be looking into a tko when the funds permit, so i can live with 3000+ at 65 mph for now
thanks for the links and info it helped a lot.
Joe

For $1900 you could get a 200R4 from Monster Transmission and upgrade your current rear to 3.73s Then you get the best of both worlds. Why buy a new rear housing unless your old one is wore slap out? Just replace the ring and pinion and upgrade the tranny. I got the complete tranny w/2200 stall, all cables, metric bolts, lock up circuit, everything to upgrade from Th350 to 200R4 for less than $1300 from Monster (eatmyshift.com) on eBay.
JMO.

jw