Well heres the deal my truck came with 3.42 gears and a G80 locking diff. Now I was planing on getting a Eaton posi and 4.10 gears, but the guy that dynoed my truck told me not to? He told me 3.42 aint that bad of a gear at all becasue theres no weight in rear of trucks and all I would do is spin forever. He said the better route would be stick with the 3.42 gears and go with a higher stall 3600 or so? Should I get a stall and shift kit or rather stick to the plans and get 4.10 Eaton then a stall and built trans?

My thinking more gears less stall or less stall more gear?

 

I would think with a higher stall you would need more traction and your G80 would not put up with the added stain from the higher stall. I could be wrong because I still have my stock converter slightly modded with 3:73 gears and can not tell you what difference the stall would do for traction.
If you do change gearing vs a stall going to a 4:10 would be fun as hell!

 

342's and a 3600
sounds mismatched to me
kinda like the 3600 tc would put alot of stress
on everything behind it with the 342s

hows the dyno graph look?
do you reall need that big of a stall?

I would think a 2800 to 3200
with 410s would work well

 

I would get the eaton regardless. If it was me I would go with the 4.10s and put a 2800-3000 stall in it depending upon how the dyno graph is.

 

Don't Sound Right I Have 4.56 In Rear And @ The Track No Traction Problems

 

It depends on the power you are making. If you are making gobs of power you dont need a low gear. I am running 3.42's with a 2500 stall. My truck makes 403hp at the wheels and runs in the 12's in a 1/4 and 7's in an 1/8.

I also had a 81 Z that I put a 454 in. I originally was running 4.10 gears and the car was running 8.80 in an 1/8. I swapped the gears to a 3.42 and the car ran 8.20.

I also have a friend that has an 1800hp drag car that he was running 4.30 gears in. He desided to swap to 4.90 gears and it slowed the car down. He then changed to 4.10's and it dropped his time from 5.0 1/8 to 4.5.

So I would stay with the 3.42. But thats just my opinion. Its all up to you. If you think you need more gear, go for it.

 

The truck needs the lower gear because of the weight and the diameter of the tires. Low gears, high stall, and some tires that will hook. You'll be happy.