Gm 7.5 setup

[Drkuhar]

so after my weighing my options of a 9" or another 7.5 i decided for my use it would be more feasible to rebuild another 7.5 and i found a nice low mile one for 50.00 but has 2.29 gears. I saw quick performance offer complete 10 bolt packages with a posi carrier, gears and bearings for 495.00. Would there be a noticible upgrade to go to the 3.73 over 3.42 (which i have in my current rearend). They are the same price and I would have to change the speedometer gear. I mostly cruise around town, take kids to school, no drag racing or anything maybe occasional burnout at a stop sign with a mostly stock 350 engine and th350 transmission. Is there any tips on building a 7.5 anyone wants to share.

 

[Bonnewagon]

3:73 gears behind a non-lockup T-350 means driving in the slow lane at 5000 rpm trying to keep up with highway traffic. If that is never going to happen then by all means go for it.

 

[64nailhead]

What tire size? If running a 28" tire, then the 3.73's will work. If running a stockish size tire, then a 3.08 would be much more suitable.

 

[Drkuhar]

I am running a 26.5 tire 255/60r15 with 3.42 now . Im at around 2800 rpm at 55. I dont think there would be that much change at 3.73 and since i seldom leave the small towns around me it probably wouldnt matter. Just wondered if it would be a noticible change or negligible between the two ratio's.
Im also looking for tips/tricks to set up this new rearend. Should i used the spacers in it now to start dialing in the gear mesh etc

 

[83StreetMachine]

I personally wouldn't go through the effort if you already have 3:42s

 

[Drkuhar]

I personally wouldn't go through the effort if you already have 3:42s

This rearend im using came out of a car the was wrecked and it repeatedly goes through front seals. So i want to build one that in one day i can swap out

 

[superbon54]

When I switched from 3.42 to 3.73, I hated it on the street. It didn’t seem all that much peppier, and the drone on the highway became terrible.

Is your current rear shot?

 

[Drkuhar]

When I switched from 3.42 to 3.73, I hated it on the street. It didn’t seem all that much peppier, and the drone on the highway became terrible.

Is your current rear shot?

My current rear end came out of a car that was wrecked. I had to change an axle and it rides smooth now but goes through front seals. I was going to build one that would be a quick swap.
Your answer is what i was looking for. Not much peppier but more drone. I didnt think there would be much difference

 

[83StreetMachine]

This rearend im using came out of a car the was wrecked and it repeatedly goes through front seals. So i want to build one that in one day i can swap out

Ah ok. That makes more sense then. I'd just get the new to you housing, rebuild it, and just swap your guts into it and hopefully you end your seal problems.

I think 3.42 is the best ratio for a 3 speed auto. I have one in my car.

 

[pontiacgp]

This rearend im using came out of a car the was wrecked and it repeatedly goes through front seals. So i want to build one that in one day i can swap out

did you replaced the bearing and races when you changed the seal?......