Right now I have a stock 1974 Camaro with a L65 motor ( 2bbl ) Rated at 145hp. I plan on doing a engine upgrade in the near future to about 300 to 325 hp. The car will be street driven most of the time, except for some stop light to stop light fun. The current gear is a 2.73 open rear end. I'm thinking of changing it to a 3.42 limited slip posi. Is this a good all around gear or should I go for 3.73 limited slip posi ? Also the car has a stock turbo 350 transmission that I plan on having rebuilt. What should i have done to the turbo 350 trans? Thinking of a 1600 or 1800 stall converter, I still want drive ability. What do you guys think. Any and all suggestion will be appreciated, Thanks

 

3.73s with a TH350 rev quite high on the highway, with a 4 speed and overdrive its no problem though. For that reason i would say 3.42. For the record i had a 350 with TH350 and 3.73 before i rebuilt my car.

As for the transmission, some high temp steels, high friction clutches, upgraded sprag and a TCI valve body with increased pressures would allow it to live a long time. Someone else might be able to give more advice on this but i would think a 1800 stall is really really low, my TH350 had a 3500 stall and it was fine so i would think somewhere in the 2500 range would still be very drivable

 

3.42 is a good choice for most cars with tires around 25"-26" tall. If you were running taller tires in the 28"-30" range, then I'd go 3.73, but most 2nd gen owners aren't running anything that tall.

 

I'm running 25" tall tires. Do you know what the stock torque converter is 1200 or ? I just want to make sure this car is street-able that's why I was thinking / guessing at a 1800 stall torque converter. The 3.42 gears are what I plan on going with now. Thanks for all your input.

 

Stall speed will be determined by your cam. You will want your stall speed to be at or just below where the cam starts making the most power. I'll be running a 2800 rpm stall with my cam..which is considered on the low end of the range compared to others with the same cam.

 

You also want to be sure the stall speed is lower than your cruising speed on the highway. So with your TH350, 25" tire, and a cruise speed of 60mph, your engine rpm will be 2758. So you need to be below that for the stall speed.
I believe the stock converter is in the 1600 rpm range, and I'm unsure what your cam might be with 300-325 hp, but don't think you'll have a problem with a 2200-2500 stall.

 

You should really research the 700-r4 upgrade or even the 200-4r. Since you are already thinking about rebuilding th350 the cost would only a few hundred more.

The 200-4r is a direct bolt in cross member and drive shaft wise. I believe these where stock in the 80 and 81's so all the shifter parts should be around.

Just looking at the gearing the 700-r4 with 373 will have a much stronger launch then the Th350 with 342.

If I have a second gen non-Z28 my first upgrade would be 4 Speed automatic, well I am a stick guy so it would be a 6 speed manual but either way it would have OD.

 

The 200-4r is a better choice, and not just because it bolts up easily. The 700r4 does have a very low 1st gear, but with 3.73 and low profile tires, almost too low. It makes 1st gear almost like a granny gear on an old truck 4 speed. The 200's taller 1st gear would be better with 3.73 rear gears.

 

I had my "78" rebuilt with 3.42 and am happy with it . Cruses nice on the freeway, but still comes off the line good. I'm also running a 2400 stall and like it.