TBI engine for 1977 truck

[Ron T]

Looking for information on best route to go with my project. I have a 1977 Scottsdale. Half ton short bed 4x4. It is a rolling chassis that had a 350 with a manual transmission in it. The engine was removed long ago but bought the truck to one day rebuild. My 12 year old son has decided it is what he wants to have. So the first goal is to just get it up and operational. I am looking for the best way to do this with what I have available right now. Right now I have a 1995 2500 4x4 with a 305 and automatic transmission. The other parts I have in the barn are the 1977 transfer case and a 350 transmission. I am a pretty decent mechanic as it goes but lack in the conversion knowledge. This is where I am looking for advice. What is the best conversion to do to just get to reliable right now. Can I take the entire drive train out of the 95 and drop it into the 77? (eng., trans, and transfer case) Should I just use the 305, dump the TBI setup and use the 350 trans and original transfer case? Your thoughts and knowledge are appreciated.

 

[bucket]

What kind of budget do you have? What is the transfer case and is it what came behind the th350? Those items often don't mix and match well.

My experience with all my TBI setups is good, they have all been dead reliable.

 

[Ron T]

My budget is not crazy. lol My wife and I have 8 adopted kids so trying to keep it reasonable. The transfer case came out of another 78 and was bolted to the 350 trans. Can I drop the whole drive train from the 95 into it fairly easy? I know there will probably be some fabrication on the Transmission mounting crossmember and the drive shaft. But what about the electronics? Do I pull wiring harness and computer and purchase whatever kit I need to make it work? We will eventually want to do a full restore and ls swap as he is in high school I am sure. But for now it would be nice to just be able to use it on the farm and to run into town. As far as actual budget, I guess I am kinda looking for a ballpark number I can chew on. Thanks for your help.

 

[bucket]

Sounds like my kind of budget, lol. I've got 7 and an 8th coming later this year.

The best bet for simplicity, reliability and cost would be to use the TBI motor with the 77's trans and t-case. A TBI swap harness could be your one "splurge". You could reuse the factory TBI harness, but there are complications to sort through. A harness from Painless (or similar) is almost idiot-proof.

 

[1987 GMC Jimmy]

@gmachinz should have a suitable replacement TBI harness much cheaper than painless. If you really want to stretch it, you could always reuse the factory harness.

 

[HotRodPC]

If you really want to cheap out, you can use that Th350 and that NP203 Full time transfer case from the 78 and change the intake on the TBI engine and go Carb. You can't use that 95 Transfer case unless you want to get into swapping front axles cuz the NBS GMT400 used a Driver Side drop instead of a Passenger Side Drop. Also, the 95 Transmission while it does have OD, it's a computer controlled transmission and 4L60-E, especially that early on, isn't the strongest choice at all.

350 engine with a Intake and Carb Swap, Th350 Transmission with the NP203 Full Time 4x4 will be Simple Simon and durable, just not the best on mpg which none of these bricks for a truck ever are.

On the other side, you could find an NP208 or NP241C Transfer Case to hook behind that 4L60-E and 350 TBI. Even though the transmission is computer controlled, if you're going to run the TBI, you're going to install the computer anyway and the same ECM that controls the engine will also control the transmission. Just be sure to get a Transfer Case with VSS (Vehicle Speed Sensor) to control the transmission, which means you'd need to get the correct instrument cluster to operate a speedometer. You'll also need to change the fuel pump to an in tank electrick pump or high pressure external for the TBI. Probably should change the tank too since you'll need a tank with a sump for the internal E pump.

 

[bucket]

If you really want to cheap out, you can use that Th350 and that NP203 Full time transfer case from the 78 and change the intake on the TBI engine and go Carb. You can't use that 95 Transfer case unless you want to get into swapping front axles cuz the NBS GMT400 used a Driver Side drop instead of a Passenger Side Drop. Also, the 95 Transmission while it does have OD, it's a computer controlled transmission and 4L60-E, especially that early on, isn't the strongest choice at all.

He said it's a '95 2500, so it should have the 4L80e. But, budget and simplicity was the goal so swapping that trans in wouldn't really be ideal either.

But, if it actually is the 4L60e, then the 203 t-case from behind the th350 would work. Just trim the output shaft down and use a spacer.

Either way, just running the th350 that the truck is setup for would be the easiest route.

 

[HotRodPC]

Yep, I didn't catch the 2500. I just caught 95 for TBI and E controlled Transmission.

 

[75gmck25]

One other question - You said the engine was gone, but does the truck still have the original manual transmission and transfer case? If so, it should be an NP205 part time case. You may want to use that t-case yourself, or you may want to put it up for sale. It should be very easy to find a buyer for an NP205.

The transfer case bolted to the TH350 should be an NP203. Its not the favorite transfer case for most folks, but I have one that is still a full-time case and it will take a lot of abuse. I would not modify it for part-time. Many folks that do that mod do not run it 4WD periodically to keep the entire case lubricated, and it will not last if its not lubricated.

Bruce

 

[Galane]

If you go with the vintage transmission and transfer you'll have to come up with a flywheel to match the external balance requirements of the 1995 engine. Then you'll need something customized with the ECM to take care of the missing electronic controlled transmission. You'll also have to adapt the VSS to the 1977 drivetrain.

What may be your best bet is to locate a cheap mid 90's donor truck then sell all the drivetrain parts you have to pay for it. Then you'll have everything from one source, already made to work together. Check your local Craigslist. That's how I found the 1991 stuff for my 82 GMC for cheap*.

https://geo.craigslist.org/iso/us/mo

What are the emissions rules like in Missouri? Good thing you're not in California because you'd find it difficult to do a job like this on a 1977 half ton. Probably be stuck with putting the 1977 carb on it along with having to somehow come up with an AIR pump, if it had one, and all the other headaches.
In CA they require emissions controls to be maintained as they came from the factory, despite the Federal 25 year and older exemption. Yup, they made it illegal to make a vehicle *pollute less* than when it was new. For a one ton truck it's no problem. They weren't required to have any emissions controls, even in California, until sometime in the late 80's or early 90's.

*Then I proceeded to pour bunches of $ into it. And I'm having to take the engine apart again because shortly after I got it running perfect last fall it decided to clatter and run crappy. Got it out and upside down on the stand. New crank and bearings are fine but I can see a crack in a piston skirt and there's lots of iron powder in the oil.

 

[Ron T]

Sorry for the delay in getting back to all of you. Been having to work to many 24 hour shifts, baseball season for three boys on different teams and ect. I want to thank all of you for your information and your willingness to share it. In Missouri we don't have any emmissions to worry about. I do have the manual transmission and transfer case that came out of the truck. I also have a 350 automatic trans, transfer case, torque converter, flywheel, starter and drive shafts that I picked up from a 78 also. Ive pulled the truck up to the shop building and will get all of the parts laid out and properly identified this wkend, so I can let y'all know exactly what I have to work with. I do know that the 77 had a part time transfer case in it and a manual locking hubs front axle. I look forward to more suggestions and knowledge once I've given you the rest of the information. Thanks again.

 

[4WDKC]

cheapest route is carb 305/th350/203 let him drive it and save money till he decides to LS swap it.