craparo

iTrader: (3)

Okay.. so I need to put a th400 in the car, and I want too, I just hate the fact of losing O/D... just for minimal street driving, but to get anywhere in So. Cal you have to use the highway which requires ~65mph cruising speed....

Talking to Yank they said going with 2.73 rear gears and a 400 I would be cruising 80mph just fine (i think they said 2500 or 3000rpms)...

I currently have 4.10s and drag racing/launching are important aspects of the car.

Stepping down to 3.73s don't appear to give me enough mph difference to justify the work/money in swapping.

3.42s and 3.23s might be feasable, I was just wondering if anyone has done something similiar and about how much performance in the 1/4 I will lose, by stepping away from my 4.10s?

Or maybe keeping the 4.10s and th400 will work alright for my setup? Sometimes to goto meets and such the car will have to be on the highway for 20 miles straight at a time.

Any help would be greatly appreciated (I am searching this too, just posting for some real-word experience replies too)

z28hustle

some one should answer this i would like to know too

john kilgore

run a long rear gear and put a bigger number in the th400.

JL ws-6

iTrader: (50)

I have a th400, loose *** converter and 4.10's. I run around on a 27 inch hoosier QTP most of the time, and at 65, it about 3500 rpm or so.. kind of excessive. I dropped my highway speeds to about 55, and that keeps it closer to 3000. If you were to put a 28 inch tire on the car, you could run at 65 at about 3400, or 55 at about 2900 give or take. It doesn't drop the RPM a ton, but helps some. I haven't tested the theory yet, but I think that by going to a 3.73 and a 28 inch tire you could get to about 3200 or so at 65, which is getting more livable. With 3.42's and a 28 inch tire you'd be under 3000 I'm sure.

How much the rear gear will effect your car's speeds at the track, will depend on the setup, if it's a FI/turbo/nitrous car, a set of 3.73's would probably help get you off the limiter at the end of the track.. if it's an NA car, then the lower the gear ratio, the slower you will go.

My personal solution to this problem is that I am planning on picking up another set of rear bogart rims, and sticking the 275/60/15 et radial on which will fit without any real mods to the car, I will probably lower the back an inch to get the rake back to normal a little bit, cintinue to run the 27 inch qtp at the track, and probably go to a set of 3.73 gears. My highway travel is limited to a 20 mile or so trip every now and then as well... so I understand the situation. The 3.73 gearing will probably help my track times as well once I out some juice on my car, a small 150 hit is all I plan, but that should be enough to get the car to a 9.90 run.. which is all I want to see anyway.