Trans and rear end help

[biggpoppa3]

I just got a 1970 c10 with a 250 I6 and a three on the tree, I need to know what I could do to get it to run faster than 55 mph. I have a th350 transmission sitting at home that i plan on putting in it so I need to know if it will even bolt to the engine at all and how much stuff would i have to change to make it work i do have an aftermarket floor shifter for it. I dont want to swap the I6 for a v8 either I want the I6. Also im not sure what gears i have in the rear end but all I know is it is low so what gears should I use, i want to be able to run 70 - 80 mph easy so what gears and what could i pull them out of or what axles will interchange with mine any info would be extemely helpfull.

[Shaky]

The TH350 will bolt to the six, however you won't be able to run 70-80 mph comfortably with that trans.

The highest (lowest numerically) rear that is reasonable would be 3.07, but that still won't get you there. You're going to need to go to a TH700R4 or other 4-speed auto with overdrive 4th.

You might want to look at getting a 5-speed that has an overdrive. It might end up being cheaper than converting to the 4-speed auto.

Some people don't think anything of converting auto-to-manual and vice versa, but after doing it a couple of time myself, I keep the truck with the type of trans it came with.

[Wrenchbender Ret]

Im with Shaky. Its a lot easier to keep the manual trans. You could change your rear end to a 3.08 which many of these trucks have so are readily available or put in a T-5 5 speed o-drive trans from a s-10 pickup.

[Shaky]

Originally Posted by Wrenchbender Ret

Im with Shaky. Its a lot easier to keep the manual trans. You could change your rear end to a 3.08 which many of these trucks have so are readily available or put in a T-5 5 speed o-drive trans from a s-10 pickup.

I must be getting old, the conversion is too much for me.

In my experience the 3.07/3.08 rear with a 1:1 top gear in the trans won't get you where you want to go. We drove to Alaska in a '67 with a 3-on-the-tree and a 3.07. We were pretty much 65 mph all the way.

Combine the 3.07 and the 5-speed and you'll be flying....

[Longhorn Man]

if 55 is your top speed, then your engine is sick.
a TH350 won't help.
If your rear is original, and not oprioned otherwise, then you should have a 7.73 gear out back.
A 3.07 will get your RPMs down considerably, and down into the torque powerband of your engine. You'll be spinning 2500-ish RPMs on the freeway at 60.

[stsalvage]

Boy i love the inline 6 guys Never see the young kids wanting to mess with them.Now if your engine is sick like long horn man thinks then the 1966--74 250 Nova engines will be the Same inline six different engine brackets tons of them around.Now there are tons of them 6 lug chevy rear ends around get one that had a Automatic in it.Now I have a old man 75 years old man that is a speed demon goes out to the salt flats every year.to Prefect his inline 6's He's got a 1969 Chevy truck that he's converted over to 700R4 with a Volvo Gear Vender with 3 deuces at 400 cfm carbs and he's really can Light it up at the light He like playing with them New Camaro's with that 500HP with that 1969 short bed.Now he tells me that they get the best of him on the starts But on long open runs Gearing is what Kills any new car None of them Have it.But a guy I read about in One of the muscle car mags took a 2011 camaro and put one of them Gear venders in he talked about that he can stay up with some of the fast car's on the drag strip but out on the open Road Unlimited high Gear