I am going to re-build the rearend on my 69 350 h.o. I am leaning toward 3;55 gears but could go with 3;73. What is the general consensus out there for great performance and still retain decent highway driveability?

3.55

Do you have an overdrive? And how much highway driving do you do?
I am thinking 3.55 for myself but I have an overdrive, and will frequently drive on the freeway.

I have been looking at this website, so see my RPMs at any speed

http://www.slowgt.com/Calc1.htm#RPMInGear

bastereo.
what o/d did you go with? thinking of this and the posi rear-end change myself. what gear work best with your o/d ?
thanks

Most of us are running 400's and 455's so the 3.55 is the best bet. With your 350 HO, which likes the higher revs, the 3.73 may be better. Tire height must also be entered in equation. If you know the RPM that you like to cruise at, work backwards from that.
Jim

Thanks 4 the info all, at this altitude and the tire size 3.73 would be 3509 rpm at 70 mph. and 3.55 would be 3340 at 70 mph.

I have a 700R4 but it is only temporary, I want a TKO 600. I havent changed the rear yet, have other things to do first, but I am fairly set on 3.55 with posi. With the stock 2.56 gears, 1500-1800 rpm on the freeway. But in town is not as much fun as it should be

Hey Bill
Depending on what rear end you have, you can only go so high on a rebuild. I have a 2.56 and can only change the gears up to 3.23 unless I change the pumpkin. In that case, you might as well get a whole new setup.
However, I think PMI has hit the nail on the head, stick with 3.55.

you might want to look into getting an 8.5" out of a nova, they are much stronger and cheeper