What's the best model or year TURBO 350 to use in my truck?

Question

I have a 2003 VORTEC 4.3 V-6 Chevy S-10 and would like to swap out my current 4 speed automatic with a TURBO 350 with overdrive. It's 2 wheel drive and I plan to upgrade the rear to a 3:73 posi. Can anyone recommend the best application for me to use?

Answer 1

For a basic swap, I would use something in the years of 70-73 as they were tough and indestructable. I do have to qualify something here. Your truck is equipped with a PCM that runs the powertrain, hence the P in PCM. That includes shift points and outputs from the trans. to let the PCM know where to shift, what gear its in, pressures inside the trans., and how fast the output shaft is spinning. The THM has no inputs or outputs like this and would make the truck run funny as the PCM would inhibit the motor because of a lack of tranny data. If you can address that stuff, go ahead.

Answer 2

Seether, I would definitely stick with the transmission in your truck and do the shift kit modification! It has an overdrive and it's a four-speed. The gear spreads in the standard automatic transmission are great. You may want to add a slightly higher stall speed torque converter to launch the little Ford killer.

The latest and greatest turbo-hydro 350 form the late 80's is only a three speed with a torque converter lock-out.

If you want to get really nasty search around for a modified turbo-hydro 400. Although it's only a three speed it'll stand all the horsepower you can make. The 400 transmission is bullet proof. It's miles ahead of any 350 trans.

Answer 3

I don't think there WERE any t-350's with O/D. Why would you WANT to make this swap? Seems like a waste of money to me. The tranny you have is strong enough for the 4.3 if you have it built by a reputable builder.