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kaneerarchery
September 2nd, 2013, 02:50 PM
I am a new member to this forum. I just purchased a1966 GMC stepside. It originally had an inline 6. It has been replaced with a mid 1970's Chevy 350. There is no transmission. I would like to put an inline 6 back into the truck. The truck has a 3 speed column without a shift lever as well as a hole in the floor where a floor shifter was added. What floor shift transmissions or automatic transmissions are recommended for inline 6's.

raycow
September 2nd, 2013, 10:18 PM
You didn't say how you planned to use the truck. For general purpose driving with occasional hauling not exceeding the truck's GVW, I like the T-5. If an automatic, the 200-4R. Both of these transmissions have overdrive, which will make highway driving much more pleasant. If the truck is presently set up for a manual, the T-5 will be a lot less work to install than the 200-4R.

If you have a more specialized usage in mind, please describe it.

Ray

kaneerarchery
September 3rd, 2013, 02:03 AM
I would like to drive it about 50 miles per week. Will the t-5 bolt up to an inline 6 without an adapter. What donor vehicle should I look to pull a t- 5 from.

quest
September 3rd, 2013, 06:15 PM
I think you can find the T5 easily at your local pick n pull. they're pretty common GM 5 spd I think. it's easy to research on google about what to look for. Do you have a drive shaft, if not you will likely have to get one custom fitted with a non stock setup anyway. If you are going back to the I6 then a stock 3 on the tree will be fine, kinda depend on the rear end ratio you have and how much hiway driving you think you will do, over drive with 373's is good for that. With the T5 you will need to see where the shifter would end up coming out in the floor, you may have some mods to make if it isn't in the same spot.
Good Luck, sounds like fun.

raycow
September 4th, 2013, 12:06 AM
Will the t-5 bolt up to an inline 6 without an adapter. What donor vehicle should I look to pull a t- 5 from.
A T-5 from a 1992 or earlier Camaro or S-10 will have the correct bolt pattern. The Camaro will bolt to your bellhousing with no modifications except for replacing the clutch disc. The S-10 requires the input shaft pilot and bearing retainer to be shortened about 1/2", or you can use a commercial spacer plate like this:
http://hamiltonintakes.com/products/s10-t-5-swap-adapter

IMO, the S-10 is preferable to the Camaro because of the shifter location. I have had an S-10 gearbox in my 60 C-10 for about 12 years now and I am totally satisfied with it.

Ray

kaneerarchery
September 4th, 2013, 03:38 AM
Thanks for all of the good information.

kieth
April 3rd, 2014, 02:24 PM
I am a new member to this forum. I just purchased a1966 GMC stepside. It originally had an inline 6. It has been replaced with a mid 1970's Chevy 350. There is no transmission. I would like to put an inline 6 back into the truck. The truck has a 3 speed column without a shift lever as well as a hole in the floor where a floor shifter was added. What floor shift transmissions or automatic transmissions are recommended for inline 6's.

I have a 250 6 cylinder that we removed from my 66 gmc complete engine with accessories, transmission still attached would take 200.00 for it. Kieth

here is a picture:
http://kieth.smugmug.com/Trucks/66-GMC/i-T3x6Tkd

bigblockv6
April 4th, 2014, 12:12 AM
For 1966 inline sixes there were two 4 speed transmission choices, the GM SM-420 and the New Process NP-435GA. For automatics there was the 2 speed Pow-R-Flow(otherwise known as the Powerglide). If you're considering any of the 4 speed transmissions mentioned you will need to the taller transmission floor cover.