Can I have my cake and eat it too?

[Chas Henderson #28127]

I have a Top Flight 71 sb-auto that I want to put an 0.7 : 1 over drive gear in stead of the 1 : 1 third gear I have now. Then if I use a shift kit and reset the shift points, would this work? Is it even possible? The turbo-hydramatic 400 with my 3:36 rear end has my engine turning 3100 at 70 mph. With a 0.7:1 gear it would drop it down to a nice 2200-2300 rpm. at 70 mph. I drive the car quite alot in the summer. I know That I could go with a different tranny and install the overdrive kit on the gearshift, but would like to keep it looking like it should. Any thoughts?

[Wayne P.]

Re: Can I have my cake and eat it too?

Keep enjoying it just like it is. We're all used to the new cars idling down the highway, but they ran this fast and a lot faster for many years. For an occasional driver you'll never wear it out. The tranmission change you describe sounds like more than most shops could accomplish.

[William C.]

Re: Can I have my cake and eat it too?

Check the archives, there was a thread a while back about putting a 700-r4 in a earlier Corvette, and there were some recommended transmissins to use that were relatively an easy "bolt-in"

[Patrick H.]

Re: Can I have my cake and eat it too?

I'd leave it as was suggested above. My 71 has the same rear and it never bothers me. If you don't like the 3.36, try a 4.11 250 miles each way to Bloomington (the original location) some time. Ya wanna talk about high revs...?

The alternative is a 1971-style 3.08, or a 2.87 or 2.72 from an 81 or 82 if they'll fit. You could always swap out the entire rear crossmemnber and differential from one of those later years.

Patrick

[Mike M.]

Re: Can I have my cake and eat it too?

suggest you check the speedometer gears as a 3.70 to 1 at 3000 rpms will run the car at 70 miles an hour as a general rule of thumb. leave it alone. mike

[Mike Cobine]

Re: Can I have my cake and eat it too?

With his probable 26 inch tire, 3000 rpm and 3.36 gives 69 mph. To match it with a 3.70, you need a 29 inch tire.

See the URL below.

http://www.angelfire.com/fl/procrastination/rear.html

[Chas Henderson #28127]

Re: Can I have my cake and eat it too?

I guess that I can't! I have already read the articles in the mags and the other threads. I even talked to a shop that offers the swap. Just wanted to know if putting a over-drive into my tranny by switching it with my 3rd gear was possible. Thanks to all.