Trying to do the logical thing.

[cj847]

I am debating a 700R4 swap for my 71.

My truck has a crate 350 with a nicely built TH350 transmission. I recently had to rebuild the rear end, so......I changed from a 3.08 open to a 3.73 with full case detroit locker

So, basically, the truck is great right now and doesn't need a transmission. But, at 70mph I am at 3100 -3200 rpm. With a 700R4 it would be 2200rpm. I drive it about 10 gal of gas a week.

So, logic says:
-A 350 chevy can run 3200 rpm all day no problem.
-At $2/gal the cost save on gas would be $6/wk = $300/wk.

Is there any reason I should move forward with a 700R4 swap other than the sound it makes on the freeway?