swapping transmissions while swapping motors??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

draggin49 · 07-13-2013, 06:19 PM

Well, just got some bad news , the original motor in my truck has significant damage, so I will be replacing it.

Would it be worth swapping transmissions too while im at it?? I personally am not a fan of 3 on the tree manual, and the truck came with the lowest gear ratio offered so I was thinking overdrive might make it far more practical due to the fact I have to get on the freeway to get to surrounding cities on a regular basis.

How difficult is it to put an overdrive automatic in place of the stock manual tranny??
What items must be done to make it work??

I will be keeping it small block powered, so maybe I can find a used motor/trans combo
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68gmsee · 07-13-2013, 09:11 PM

Since you're going to be redoing the truck, see if you can locate a friendlier rear axle like a 3.08. Along with a OD automatic like a 700R4 it would be easier on the mpg. On my 69 I removed the 250 three on the column and went with a 350/TH350 from a 77 impala and rear end from a parts truck. It helped on the highway and improved gas mileage a little.

The problem for you is finding the parts. Back in the early 80's there were still quite a few 67-72 chevy trucks in salvage yards. If you can find a parts truck that would be your best bet.

draggin49 · 07-13-2013, 10:51 PM

What mods to make the new automatic transmission be shifted on the column??
Or do people usually run floor shifters after switching to automatics??

Ive never done a swap on a truck, on all my cars I went the floor shifter route.
Most of those cars had bucket seats though.

Might be able to obtain a 283 from a friend for really cheap. Worth getting or should I only stick with a 350 ?? truck is mainly gonna be a cruiser, not trying to make it a performance vehicle
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mmiddle · 07-13-2013, 11:29 PM

If you can afford it, Buy a brand new GM Good Wrench stock replacement crate motor and find a good used 700R4. The cross member and shifter linkage are going to cause you the most problem, but not major. Most people use a floor shifter because the standard shift column does not have the Park/reverse detents.

draggin49 · 07-14-2013, 12:53 AM

I will say, I purchased a GM crate motor for my 1969 camaro and never had one issue.
Probably the safest route to go
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07-13-2013, 06:19 PM	#1
draggin49 Registered User Join Date: Feb 2013 Location: Ojai, CA Posts: 361	swapping transmissions while swapping motors??? Well, just got some bad news , the original motor in my truck has significant damage, so I will be replacing it. Would it be worth swapping transmissions too while im at it?? I personally am not a fan of 3 on the tree manual, and the truck came with the lowest gear ratio offered so I was thinking overdrive might make it far more practical due to the fact I have to get on the freeway to get to surrounding cities on a regular basis. How difficult is it to put an overdrive automatic in place of the stock manual tranny?? What items must be done to make it work?? I will be keeping it small block powered, so maybe I can find a used motor/trans combo Posted via Mobile Device

07-13-2013, 09:11 PM	#2
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: swapping transmissions while swapping motors??? Since you're going to be redoing the truck, see if you can locate a friendlier rear axle like a 3.08. Along with a OD automatic like a 700R4 it would be easier on the mpg. On my 69 I removed the 250 three on the column and went with a 350/TH350 from a 77 impala and rear end from a parts truck. It helped on the highway and improved gas mileage a little. The problem for you is finding the parts. Back in the early 80's there were still quite a few 67-72 chevy trucks in salvage yards. If you can find a parts truck that would be your best bet. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

07-13-2013, 10:51 PM	#3
draggin49 Registered User Join Date: Feb 2013 Location: Ojai, CA Posts: 361	Re: swapping transmissions while swapping motors??? What mods to make the new automatic transmission be shifted on the column?? Or do people usually run floor shifters after switching to automatics?? Ive never done a swap on a truck, on all my cars I went the floor shifter route. Most of those cars had bucket seats though. Might be able to obtain a 283 from a friend for really cheap. Worth getting or should I only stick with a 350 ?? truck is mainly gonna be a cruiser, not trying to make it a performance vehicle Posted via Mobile Device

07-13-2013, 11:29 PM	#4
mmiddle Registered User Join Date: Jul 2013 Location: Forestburg, Texas Posts: 659	Re: swapping transmissions while swapping motors??? If you can afford it, Buy a brand new GM Good Wrench stock replacement crate motor and find a good used 700R4. The cross member and shifter linkage are going to cause you the most problem, but not major. Most people use a floor shifter because the standard shift column does not have the Park/reverse detents. __________________ Mark Jesus is the Way! 2003 2500HD CCLB Duramax/Ali (Clifford) 2014 2SS/RS black on black Camaro (Betty) 2006 Pontiac SOLSTICE silver/black (Lula-Bell) 1970 C/10 Short Wide (Peggy) 1964 C/10 Short Step (Hambone) RIP Jimmy Hamilton Thank you for the trucks

07-14-2013, 12:53 AM	#5
draggin49 Registered User Join Date: Feb 2013 Location: Ojai, CA Posts: 361	Re: swapping transmissions while swapping motors??? I will say, I purchased a GM crate motor for my 1969 camaro and never had one issue. Probably the safest route to go Posted via Mobile Device



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