Ghettobird52

Hey all so i have a L05 350 Tbi with the stock 2.73 rearend and stock non rebuilt 700R4. I already have zero traction off the line above 60-70% throttle in first, but i want to go to a posi rearend mostlikely 3.42 or 3.73 gearing. Would this help my traction or only worsen it? I.E do i need to upgrade to bigger size tires/wheels? Im still on stock 245/50R16 at all 4 corners

Thanks all for your time and input!

big gear head

Any time you get both rear tires pulling it will help with traction.

Ghettobird52

Thats what i was thinking just didnt know if throwing in a shorter gear ratio would mess up that transition.

big gear head

The gear is going to give you more torque at the tires, so it will be easier to spin the tires, but you will have both tires pulling, which makes a big difference.

JdubRS

I recently went from the stock open 2.73 geared rear to a rebuild 4th gen with limited slip and 3.73s. I also added tubular rear control arms at the same time and KYB struts and shocks. I have a mostly stock 305 TBI and 700r4. Traction wasn't great before and still isn't awesome now. With the combination of the gears and limited slip it definitely accelerates out of the hole better. Both tires definitely spin, it's more fun and it helped a lot when accelerating out of corners.

Pro Built Automatics

Add a posi with the 2.73's and add a 9.5" torque converter with a 2,400 rpm stall, and better hooking tires, and possible suspension mods if needed. This way you can pick up 4 - 7 tenths in the quarter mile and still have the gas mileage and low rpm's of the 2.73's. With going to 3.73's and a posi it will feel much more responsive around town, but at the best give you 2 tenths in the quarter mile and that is with perfect traction. Now you have the gas mileage loss and the higher rpm's of the 3.73's. The torque converter will give you much more than gears in terms of real performance gains. If you drive aggressively, then a 2,600 - 2,800 rpm stall torque converter might be better here. The 9.5" torque converter weighs apx. 15 -17 pounds less than the stock torque converter and that also helps acceleration over the heavier torque converter.

TURBOTOMMY

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TURBOTOMMY

Ive never had any loss in fuel mileage when changing rear gear ratios,,actually ive gotten a bump up in mileage more than once..Ive changed a hellu lot of them too,,mostly in Chevy trucks.....

Pat Hall

iTrader: (31)

Yeah, 2.73 is a crap ratio. That can be argued by some, but I'd say it's more fact than opinion. My 89 RS originally had the 305 TBI/700r4 with a 2.73, peg-leg rear. I put a 3.42 posi rear in it, and the change was awesome! I would recommend not going any lower than 3.42. 3.73 is a bit too low, especially with the 3.06 1st gear ratio in the 700r4. With 3.73's, 1st gear would only last like 5 to 10 feet before the trans will shift into 2nd. I've now got a Super-Rammed 350 in mine. I've found that 3.23 gears are enough for a 350 powered 3rd gen, but for the underpowered 305 TBI/700r4 combo, 3.42's are pretty much perfect. And even better of course with posi-traction.

JdubRS

It was a pretty major difference for me going from 2.73s to 3.73s, and I agree, 2.73s are a pretty cruddy ratio in this application. The gear change really woke the car up, that's for sure.