86 Silverado Father and Son project

[mcbassin]

Moved from the engine and drivetrain section because this turned into a real project!



I am "helping" my son build a truck to drive. So we purchased a 86 swb that needs an engine. Today we purchased a car with a donor engine 92 Buick roadmaster with a 5.7 tbi engine and I think a 700r4 tranny. The first question can I do a direct swap and use the ecu and harness and keep the throttle body? or would be better off throwing the old carburator and intake off the oem 305? Has anyone done this type of swap? can we use the 700r4? I hope to use the serpentine belt setup and I know we probably need to address the fuel supply to the motor. What about emission crap? Can I just chuck it all in the trash? BTW,The fuel inected motor runs good and I think it would be more economical and reliable than a carb. Suggestions? Thanks,
Mike

Here is the truck:

here is the donor engine:

[cableguy0]

that setup could be a direct bolt in. what trans is currently in the truck? if its a 9 inch shaft th350 the 700r4 is a direct bolt in driveshaft will even work. same if its already a 700r4. i would leave the engine as is with the exception of the catalytic converter. the tbi runs great and it will get decent mileage. not gonna set any speed records but will be reliable.you can do the normal upgrades to get a few more ponies out of it. the serpentine setup is definately the way to go. basically drop it in as is. the only issue will be the speed sensor the car has versus a mechanical speedo drive. but there are adapter available to address that too

[mcbassin]

Thanks for the reply Cableguy, I think the tranny was a 350 TH longtail. What about wiring? Is it pretty much plug and play using the TBI harness and ecm? Does this vintage use a high pressure fuel pump located in the tank? Or is it mechanical? I think we are going to start pulling the engine and tranny today. I'm wondering, do you think we can pull it as an assembly, or will we need to seperate it at the flywheel? thanks for your help,
Mike

here is a pic of the original tranny:

[cableguy0]

the fuel pump is easy. its actually a low pressure pump. it is electric but only 15psi. as a matter of fact go find at 86 or 87 truck with tbi and steal the tank out of it and u will have a bolt in deal. just look at some trucks with that setup on it to get a good idea of the wiring. its fairly simple just need to run the powers etc to the proper places. just be very careful when you take the harness out of the car not to break anything and keep track of all grounds to ensure they all get hooked up in the truck. pull all the plastics and radiator etc out of the car pull the fan off and the serpentine brackets just make sure u get all the bolts out. the bolts are all in the same places as all of the older sbc's tho holes on the block and a couple on the heads. drop the tranny crossmember and the engine and trans should come out as a unit. they will definately go into the truck in one piece lots easier to deal with that way.

[cableguy0]

oh and i almost forgot. u will be using the power steering lines from the truck but you hafta swap the adapters out of the pumps. where the line screws into the power steering pump is removable. u need unscrew the line then unscrew the fitting that the line screws into. and swap them from one to another so the threads will match. be careful when u pull the fitting theres a spring it will pop out at you.

[mcbassin]

Thanks again Cableguy! I am hoping this goes smooth. I noticed the a/c compressor is in a different location on the truck. I defenitely think the serpentine belt is the way to go.

I am a little worried about the fuel pump/tank setup. The truck has duel tanks on it. I don't know if it's possible to use both original tanks with the original switching system?

[cableguy0]

the easiest thing to do would be to find an identical truck in the junkyard and rob the fuel system stuff.you might lose one tank but i know for sure there were fuel injected trucks with dual tanks. just would hafta see how its setup. i would however at least pull the pump and stuff out of the car just to have it even if its just a spare. its a 15psi electric in tank pump. relatively cheap. they were used in a ton vehicles. but i would find tanks out of a newer truck and steal the whole setup it will bolt right in if its an 87 or so

[mcbassin]

Made progress this afternoon. We got all the mechanical unhooked and most of the electrical. I'm still trying to figure out what all we need to keep from the 92 harness. The plan is to remove the whole harness in tact and then remove what we won't need on the 86. I tried to label everything where it goes.
I was pretty impressed with how clean the engine and tranny is. There was no noticeable leaks anywhere. The odometer shows 223k miles but the engine still runs real good and the trans shifts good. Hopefully, all will go smooth. Here is a pic:

[cableguy0]

good deal your just about there now only a few more bolts and the whole thing is out and on the ground. its a lot easier to sort the harness out once its laid out and untangled

[mcbassin]

More progress! We got the donor engine out today! (thanks Garrett for the help). Anyway, Here are the pics, it seems there are a bunch of extra wires to get rid of. Notice the number from the ecm. Hopefully, I can try to start sorting out the harness tomorrow.

[mcbassin]

Small progress. I pulled all the rest of the wiring from inside the donor, pulled the fuel tank and all the lines. Hopefully, I can use some of these parts. The car is pretty much ready for the scrap yard. We'll probably wait until the engine is running before hauling it off. Just in case we need parts off it.
Then started trying to seperate the harness and figure out the wiring. I'm totally lost on how this should be done. I noticed most of the TBI upgrades are guys just adding the system and not starting with a complete motor and tranny that was running. Maybe, I'm just lazy or crazy but I thinking I'm going to just stick it into the truck and make the connections in the truck.

I got the bulkhead connector off and tried to get the gooey glue off (messy). I hoping to leave the engine harness pretty much the way it is and intergrate the necessary truck connections like the temp, oil press, starter and anything else it takes. The truck harness is covered in oil. I guess the PO had a massive leak and it covered every wire in there. Photos:

[mcbassin]

Update:
We decided to bypass the wiring "problem" for now. We just finished stabbing the motor this evening. (no time for pics). It looks like the tranny is sitting back about 5 - 6 further than the original tranny. I'm not 100% sure yet but it looks like I may need to move the cross member back and get a different driveshaft. Man, today was the first time I crawled under the truck. I knew from looking at the engine and bay that the PO had an oil leak but, man the whole under side of the truck is COATED with oily slime. I wish I had a pressure washer. I am going to see about borrowing one. I hope to get some photos tomorrow.

[cableguy0]

there should only be a 3 inch difference between the th350 and the 4l60 mounting point. 2 inches if your trans is a 700r4 which I think it is. if your th350 has a 9 inch tail shaft the driveshaft should swap right over. if its a 6 inch shaft your about 3 inches short but getting the driveshaft out of a truck that came with a 700r4 stock shouldnt be a problem

[mcbassin]

Originally Posted by cableguy0

there should only be a 3 inch difference between the th350 and the 4l60 mounting point. 2 inches if your trans is a 700r4 which I think it is. if your th350 has a 9 inch tail shaft the driveshaft should swap right over. if its a 6 inch shaft your about 3 inches short but getting the driveshaft out of a truck that came with a 700r4 stock shouldnt be a problem

I'm not sure what tranny the truck came with. It's in the pic above in the bed of the truck. And I don't have a clue what the car had in it. I will move the cross member tomorrow and try to figure out how much too long the driveshaft is. You said the difference could be 2 inches for the 4l60? Would it be possible to find an OEM driveshaft? Maybe at a salvage? I could cut it down at work and re-weld it if necessary. I have access to TIG welder. It may need to be rebalanced though right? Thanks for your help!,
Mike

[cableguy0]

measure the tail shaft. see if its 6 or 9 inches. its a th350 in the bed of the truck.measure just the tail housing thats bolted on with the 4 bolts. make sure the clam shell mounts bolted to the engine from the car are the same as the ones on the motor from the truck.

[mcbassin]

Originally Posted by cableguy0

measure the tail shaft. see if its 6 or 9 inches. its a th350 in the bed of the truck.measure just the tail housing thats bolted on with the 4 bolts. make sure the clam shell mounts bolted to the engine from the car are the same as the ones on the motor from the truck.

I didn't change the mounts you are talking about. I thought they only made one hole pattern on those. The dist. looked pretty good in relation to the firewall, but it was dark and late by the time we got done. Hopefully, more progress today after work. Thanks,
Mike

[mcbassin]

Update:
We worked on the truck for an hour or two. Not much in the way of progress. I was able to find out it looks like we won't need a different drive shaft. I stuck the original in the tail shaft and raised it up to the rear diff. and it looks to be a pretty good fit. (I can't find the hardware for the u-joints, hope I can find some replacements). I don't know for sure how much slack is needed for suspension travel? Anyway, I am putting off the need to get started on the wiring. I was able to get all the broken studs out of the d/s exhaust manifold. (that was a pain!) I will try to get some pics. I was able to weld washers to the studs (several times) heat it up and get them out. I still have to weld the bung in the d/s for the o2 sensor.

This project has really tested my patients, so far I am losing big time! So far I have had to fight with the motor mount bolts, the tranny cross member, the exhaust manifold bolts and on and on. This is what happens when you don't do any serious wrench turning for 15 years. I hope my son doesn't get half of my short temper!......here is some pics.

engine in its new home


Cross member needs to move<----- 3"

Driveshaft front

Driveshaft rear (I need caps too)

[cableguy0]

good deal. if possible slide the carrier bearing towards the trans some and get the yoke into the trans a bit further. other than that looks good. just gotta do the wiring now

[cableguy0]

also those u joint straps are in the help section at any auto parts store.

[vsoree]

Thanks, now I know what motors in my truck, that looks just like my engine and it powerful.

[mcbassin]

Originally Posted by cableguy0

also those u joint straps are in the help section at any auto parts store.

Thanks for the info, If I remember right they have something like a 5/16-24 cap screws too. I should be able to check that pretty easy.

Also, this truck has a one piece driveshaft with no carrier. I think that there is only about an inch of travel from butted up tight to where it actually will ride.

On the wiring, I am going to wait till I have all the things I know or kinda remember how to do first. Then move on to wiring.

Mike

[cableguy0]

lol it wont be too bad. the bolts come with the strap in the package so dont worry about finding em. is it a short bed truck?

[mcbassin]

Originally Posted by cableguy0

lol it wont be too bad. the bolts come with the strap in the package so dont worry about finding em. is it a short bed truck?

Yep, it is a short wide.

[cableguy0]

the d shaft will go into the trans a bit further once u set it down on the crossmember with a mount isntead of sitting up on the pan. ideally you would want the shiny part of that yolk all the way in the trans. it will be close enough once you set the trans down

[mcbassin]

I made a threaded bung out of SS and welded it to the truck manifold.
Pics of progress:
Before

After