I have 4 f body cars and 3 of them are 3rd gens and ALL DAILY DRIVERS! All of them are 100% stock.

1. 1989 Formula with 2:73 rearend at 75mph = 1800 rpms

2. 1989 Formula 350 with 3:27 rearend at 75mph = 2300 rpms

3. 1991 camaro z-28 350 with 3:23 rearend at 75mph = 2250 rpms

4. 2001 camaro ss with 3:23 rearend at 75mph = 2250 rpms

I would think that with a rearend of 3:73 would be very close to 2800-3000 rpms.

 

This is rather simple. Drive the car at 70 mph in whatever gear is 1:1 (3rd gear in an auto, 4th gear in a manual). Your tach will tell you your axle ratio.

3230 RPM = 3.23 axle
2730 RPM = 2.73 axle
3420 RPM = 3.42 axle
3730 RPM = 3.73 axle

Multiply any of the above by 0.70 and you get your RPM in O/D.....3730 x .70 = 2600 RPM.....3420 x .70 = 2400 RPM

 

I had 3.73's in my old 92 Heritage, and it was way 2 much gear (TPI intake). After the swap, I wished I stayed with the stock gears. It went threw the tq band way 2 fast.

 

I put 3.42 gears in my 95 Z.It feels almost stock (the way GM should have built it,not with 2.73`s).The only problem with 3.42 or lower gears is that it will shift into second too quickly and you lose passing gear at highway speeds.I only rev at 2500 at 75 mph.But it only drops from 4th to 3rd above 60 mph not a big deal to me, but with the 2.73`s it would drop into 2nd and fly.Like I said 3.42`s feel stock 3.73`s might be a small compromise on the highway but would be alot of fun around town.

 

3.73's are not right for you!

 

3.73s are prefect for street or highway driving with a 4 speed auto. you will be able to drive this on the highway also, 2600rpm just make sure you get the right speedo gear or your speedo will be off...