NEED Help on Rear End

[355sDIME]

Im running a turbo 350 and want to upgrade my gears in my 7.5 rearend. Im wondering if i should run a posi and 373\'s or 342\'s. I want to put nitrous on it so which gearing should i choose?

[redneckgames]

I have 3.42 with a gov style posi in my truck. They work alright but I am going to try to find a set of 3.73 or 4.11 gears. I don\'t drive that much so I ain\'t worried about gas mileage. I don\'t recommend using the gov style posi. It works good but I have left black marks that start out posi and then goes to a one legger. IT seems that the posi kicks out too soon for my liking. Hope this helps.

[mzoomora]

The difference is negligable. A 3.73 at 60 mph with a 26\" tall tire will only turn 250 more rpm(2950). I have always liked a 3.73 myself, and that is what I run, but I also have overdrive. With a 27\" tall tire it is only 200 rpm(2800 rpm). A non-lockup or loose converter will raise those numbers some.

[speeder]

if you run nitrous on that rearend you should get a lower number gear. The reason why is because with the 373 gears and posi I had I spun the tires from launch and through most shifts on street tires. When I went to slicks to overcome this problem the rearend disintegrated. The pinion teeth all came off together. I can show you pictures if you like.

SO if you keep the gearing lower, you will spin the tires less and not have to go to slicks.

[355sDIME]

Speeder, by lower you are refering to ratio i.e. 373, or numerical i.e. 273? You are suggesting 373 so that i do not strip my pinion teeth correct?

[355sDIME]

Never mind you are saying just the opposite. I s there anyway i can bullet proof the rearend?

[speeder]

I am suggesting the lower numerical, so 342 or 308 for the nitrous. This way you will have more traction and may not have to go to slicks. When you have a higher number gear, you have more torque to the road, which means you spin the tires easier.

Nitrous makes a lot of HP, but it generates a ton of torque. my truck makes like 336HP and 370lbft on motor and 496HP and 700lbft on nitrous.

[Doug]

Never mind you are saying just the opposite. I s there anyway i can bullet proof the rearend?



By the time you buy a diff cover, a c clip eliminator, some aftermarket gears, and mabey a center section. You would still just have a 7.5\". Just put up the money up front and upgrade. 12 bolt, 9 inch, or Dana 60. I would go with the 9 inch. You will feel a lot better when you drive your trck if the rear is replaced.