What Gear do you run, and why? I noticed in the other thread that people were complaining about the overdrive with 342's and above. I have an Lt1 w/ a TH350 and Im about to install the combo and have my gears swapped. (I currently have a rear w/ 323's) So please tell me any problems you had/have and why you hate/love your gear number.

Thanks,

Bone

 

Well, as you said, it's the lack of OD. And keep in mind that anyone running one of these trannies will also have a loose converter. So, on the highway, even with 3.42's it revs too high. Noisy, wears things out, terrible fuel economy, Everyone is different though, it may not bother you. I am kind of getting used to it myself. After all, when I was a kid we drove all over the place with 3.90's, 4.10's, etc. with no OD.

Rich Krause

 

I run a 3.70 gear in my car. I do run the highway as well.

 

I've heard that its possible to run a descent gear on the highway/local like 373's with no trouble if you get a 3200 stall or similar. Any truth to it?

 

I have a th400/3800 or so stall with a 10 bolt/3.73's.. I drove it on a 500 mile trip on the freeway in one day. It sucked but is possible. Most of the driving was 3200+ rpm. I think if I put in a 9inch/12 bolt I am going to drop to 3.23's or 3.42's and use a 26" tire at the track. If you don't drive a lot of freeway you could probably go with 3.73's...

 

God, that would be a pain probably.

Thanks for the info.. anyone else wanna chime in?


[edit]

forgot to mention I'd be running 18" tires.

 

You will be running 18" wheels. When referring to tires in this context, it's the outside diameter of the tire that is usually referred to. In that context, it can make a substantial difference. What is the OD of the tire you plan to use?

Rich Krause

 

Yes, I meant wheels, but you picked that up, so it's ok.

245/40-18

Does the tire size make that much of a difference?

 

I have TH350/3.73, fun to a point. loss of OD sucks, I get 13MPG. I have a 3500 stall. 60MPH and 3k RPMs gets old, then run on the interstate at 80ish and the tach is up there. But it just depends on what you are wanting out of the set up. it is in the power as soon as you hit the gas from a roll.

I probably will end up going back to A4 for the OD.

I run a 3.73 to get me up on the RPM range for ET purposes, the car really needs 4.10s, but 3.73s is all I could get at the time. On spray though, i need 28" tall tires or less gear, leaning towards less gear.

 

Hmm, maybe 342's with a stall might be better then w/out an overdrive. : /

 

Well I dont know why I didnt think of this before. I have a GMC 1500 truck with a 305 TBI and a TH400. I just decoded the rear gear ratio as 273. This truck, is heavy, and even with the 305 it runs great. It gets crappy-*** gas mileage on long highway trips (to the junk yard near morristown) but in town the take off is very nice.. It does bog off the line, but again its a truck, and with a out of tune 305 to boot. But overall, I'm very happy with the way it takes off and drives.

TH400 Gearing

2.48 1.48 1.00

TH350 Gearing

2.52 1.52 1.00

So with the above 5.0/TH400/2.73NPS and the 235/75/15" wheels this thing has, and seeing as Im very happy with the takeoff (not the bog) and I can stomach the highway mileage, the above has to say something about what kind of gear I like? Correct?

With the displacement difference and gear difference, and the wheel size difference, I'd say 373's would maybe be overkill, and 342's would be either be pushing it, or damn near perfect. If I'm correct in my thinking : /

 

4L80E

 

No thanks

Anyone else?

 

Just trying to help.

 

I appreciate the bumpage, but if you read the first post I have a tranny already.. So I would appreciate actual gearing posts even more.