Let's Build A 1 Ton Crew Cab 4x4

[NastyBuzzard]

Let's start out with what I have and what little I know.

Here are some of the trucks I have. I will start with the prettiest one.

1988 GMC R20 SRW Crew 3+3 350TBI/TH400 4.10 gears - Runs

Current State





Here is my 1987 GMC R20 Crew 3+3 That has had the frame shortened to a short bed and a 5 lug conversion up front and one started for the rear.





This is what I picked up yesterday.

1978 GMC 1 Ton 4x4 350/th350 SRW 3+3 Crew Cab - Gears(Unknown) Runs..








As ugly as that truck is, I was still giggling pretty good when I got it to the house yesterday. $500 is what I spent on the 78. My plan was to just do a straight body swap and swap the 88 TBI setup onto the 78 frame and attach it to that th350 and just use it around the house while I actually build it up.

However, the frame on the DS under the bed is pitted pretty badly and real thin in some places, so there is that to be dealt with. Also the rear spring hangers are junk

I am not sure if I need to swap the 4x4 stuff onto the R20 frame or what exactly.

Also the 78 is currently all time 4x4, that will need to change. I am assuming a dana 60 can be converted to lock hubs or something else.


My short term plans is to figure out if I am cab swapping and fixing the rear frame or if I am making a bastard of the two. I would love to keep the bigger 1 ton frame if possible.

Medium term plans is to get it swapped and the frame shortened for a short bed which I already have ready for it and running/driving/street legal with a lift and tires.

Long term is cummins/duramax NV4500 set up or 4L80e.


I know it is going to be one hell of a struggle to get that rusty body and bed off.

I will be able to sell the 78 350 out of it since it does still run.


Any advice or insight would be appreciated. This will be a budget conscious build considering I have my 1987 GMC V1500 LS Swap in its final stages prior to paint and what not and the engine blew up in my 01 TA that I now need to build an engine for and find a T56 trans to swap in it.

[NastyBuzzard]

So a guy at work has 2- 6.5TD complete he is willing to sell me for $750. I talked to my buddy and he will split it with me and take one and I will get the other. The 94 6.5TD still has the stock trans attached to it. Not sure if it is 4L60E or 4L80E. If it is the 80 I will be trying to get it as well.

So my building my dream 1 ton is getting closer to being achieved than I thought! I mean I would really want to have a duramax but I am too poor for that.

[marvgarr68]

4l80e is the only trans behind the 6.5 no 4l60 was behind a 6.5. th400 were behind 6.2s.

[NastyBuzzard]

Originally Posted by marvgarr68

4l80e is the only trans behind the 6.5 no 4l60 was behind a 6.5. th400 were behind 6.2s.

That is good to know! I kept hearing different things. Only thing I thought I found that was conclusive was the some 6.5 non turbo's did get them.

I am excited to go check it all out after work today and get some pictures.

I am hoping this will be a somewhat straightforward of a swap though. Even though I do plan to use the electric pump instead of the mechanical pump from a 6.2 or early 6.5. Mainly because I don't mind wiring in the new harness and because I am too cheap to buy a standalone harness for the 4L80E.

Can anyone tell me if there is a manual hub swap for the Dana 60?

Also how much different are the 3/4 ton and 1 ton crew cab frames? The 1 ton as you may have guessed has some rough rust on the frame rails under the bed, specifically the ds. I am not sure if I need to patch it or just swap it over to the 3/4 ton frame which is fine.

[marvgarr68]

You can get manual hubs for the 44 you have under it already. The frames are different big time between 3/4 and 1 tons. My k20 frame is around 6 or 7 inch tall at the tallest part under cab and my c3500 is over 8 and a lot thicker. My c3500 is also a camper special 10,000 gvw which I think doesn't matter.

[NastyBuzzard]

Originally Posted by marvgarr68

You can get manual hubs for the 44 you have under it already. The frames are different big time between 3/4 and 1 tons. My k20 frame is around 6 or 7 inch tall at the tallest part under cab and my c3500 is over 8 and a lot thicker. My c3500 is also a camper special 10,000 gvw which I think doesn't matter.

I don't have a 44 currently. Well I do but it is under my 87 that I am LS swapping. The rusty 78 has the dana 60 under it.

I had looked at the two frames and I noticed they were different but I had other people tell me other wise. The rear spring hangers on the 78 4x4 1 ton are rusted away pretty much too and they seem a lot smaller than what I am used to as well. I have a spare set from a k5 I think but they look a lot different.

[marvgarr68]

I thought it had a 44 under but I looked again. I am sure there are manual hubs for 60s. As far as the rear hangers I think 3/4 and 1 ton are the same. If you are going to lift it just use shackle flip hangers and bolt them on.

[NastyBuzzard]

Originally Posted by marvgarr68

I thought it had a 44 under but I looked again. I am sure there are manual hubs for 60s. As far as the rear hangers I think 3/4 and 1 ton are the same. If you are going to lift it just use shackle flip hangers and bolt them on.

I have some hangars off a K5 or I may just make some. I am not sure I want to use shackle flip considering the potential of towing a gooseneck trailer with a tractor on it. I heard that shackle flip is not good for towing.

[marvgarr68]

I regularly put 4500 lbs in the back of my k20 with shackle flips and never had a problem. I haul water a lot.

[NastyBuzzard]

I went and checked out the engines and what not yesterday.

He wasn't lying about what he had, he just didn't store it in the matter I was hoping for.

The heads were off the engines and the intakes and what not were stored in the service body of one of the donor trucks. The donor 94 truck he still has the entire truck, and the supposed 4L80e is still in the truck. He is also missing one injection pump. He showed me the one he has and was telling me it was mechanical but I didn't see any bracketry for the throttle cable so I assume it is actually electro mechanical.

He even had the entire wiring harnesses and even had the complete dash out of one donor.

So if I get these engines and split the cost with my buddy I will have a complete 6.5 TD for around $375, since he wants $750 for it all but I may attempt to negotiate down a bit considering.

It looks like it will need to go to a machine shop to be checked out and possibly either rebuilt or at least torn down and have the normal stuff replaced.

So far it still seems like it is worth it for me though. I have a whole truck to put together without worrying about engines just yet.

Whats the rebuild cost for one of these normally run? I am not sure if I just want machine work done and I assemble it myself or what.

Also, what are some minor goodies I could add while building it back to ensure longevity?

[marvgarr68]

First thing see what number block they are. Second have them checked out for cracks in the main bearing webbing. Third guarantee the heads are cracked. You are going to be better off with the mechanical pump. The only reason I went electronic is for my adjustable tunes. As far as making them reliable keep it stock with a better flowing turbo but leave boost stock. A scat crank and fluid damper is also a good idea. Good way to spot a mech pump over an elec one is the elec one is square with a plug on top and a solenoid.

[NastyBuzzard]

Originally Posted by marvgarr68

First thing see what number block they are. Second have them checked out for cracks in the main bearing webbing. Third guarantee the heads are cracked. You are going to be better off with the mechanical pump. The only reason I went electronic is for my adjustable tunes. As far as making them reliable keep it stock with a better flowing turbo but leave boost stock. A scat crank and fluid damper is also a good idea. Good way to spot a mech pump over an elec one is the elec one is square with a plug on top and a solenoid.

This one definitely has the plug on top and solenoid.

1 engine was rebuild completely by machine shop, heads re-done and all. When the guy started it up it had a tacking noise. He took the heads off and diagnosed it as a piston wasn't assembled or torqued correctly.

The other engine has 70,000 miles. He still has the truck it came out of to prove it. He was just swapping the 6.5 for a Vortec 350 but never finished it. The only issue it had was some slight bubbling when they checked the radiator, the heads were pulled and they noticed one of the head gaskets was on its way out but not gone completely.

That is the story I have been told. They are from 94&95 year trucks. Like I said he still has the one truck the 70k mile motor is from, its a single cab with a service bed/body or whatever on it.

[marvgarr68]

They will need to be gone through completely. Still have to check for cracks in blocks. Heads on the one for head gaskets will need new heads can not surface them very well and then compression goes up. Not sure about the other never heard of a piston torqued wrong nothing to torque on a piston.

[NastyBuzzard]

Originally Posted by marvgarr68

They will need to be gone through completely. Still have to check for cracks in blocks. Heads on the one for head gaskets will need new heads can not surface them very well and then compression goes up. Not sure about the other never heard of a piston torqued wrong nothing to torque on a piston.

I thought the same about the torqueing of the piston. I assumed he meant rod or wrist pin problems or something. I am not sure.

Yeah I plan to get it all checked out for sure. I want to put it in only once.

[deejaaa1]

not sure if it's 94 or 95 but one year IP is one you want to stay away from. being year specific, it's hard/expensive to rebuild.
my 93 is mechanical. less temperamental, especially regarding the FSD because there isn't one. the 6.2 mechanical pump can be turned up and case pressure increased to match the 6.5's.
I converted my 4L80E to a manual shift. drop in 3rd, will stay there, or any other gear. just a few parts to change, real easy, no need for TCM's. will need a reverse lock-out shifter instead of the column, reason is obvious.

[NastyBuzzard]

I definitely need to do more research and learn what to stay away from before I get going with all this. I don't need another big money pit, that is for sure.

If I am running the 4l80e I want it to work as it should with OD and all.

I have heard about turning up the 6.2 pumps as well.

[marvgarr68]

As for the 94 ip 5068 it was the 94 model 6.5 but some got 5221s. The 93 6.5 were mech and had an ip made for the 6.5 specifically. The 4911 mech 6.5 ip is the best and has the most displacement. I would run the 4911 mech ip in your truck as you were looking for reliability. The 4l80 can be converted over to full manual with a transgo stage 3 kit. It will have all 4 gears and you can just run a wire to lockup the torque converter. The only problem with the setup is the tcc solenoid is a pwm not on off. If you supply it with 12v cont it will fail. Some have put a resistor in line and the solenoid last longer. If you do not want to go manual on the 4l80 a standalone control will be cheaper then making the electronic fuel injection work and last. Do not use a 6.2 ip on the 6.5 maxed it still only put out a little more then a stock setting 4911.

[NastyBuzzard]

Originally Posted by marvgarr68

As for the 94 ip 5068 it was the 94 model 6.5 but some got 5221s. The 93 6.5 were mech and had an ip made for the 6.5 specifically. The 4911 mech 6.5 ip is the best and has the most displacement. I would run the 4911 mech ip in your truck as you were looking for reliability. The 4l80 can be converted over to full manual with a transgo stage 3 kit. It will have all 4 gears and you can just run a wire to lockup the torque converter. The only problem with the setup is the tcc solenoid is a pwm not on off. If you supply it with 12v cont it will fail. Some have put a resistor in line and the solenoid last longer. If you do not want to go manual on the 4l80 a standalone control will be cheaper then making the electronic fuel injection work and last. Do not use a 6.2 ip on the 6.5 maxed it still only put out a little more then a stock setting 4911.

It is amazing how much different opinions I keep hearing! Especially about the 6.2 pump. I have also heard making the electric fuel injection work is piece of cake.

I am not afraid of integrating the wiring... You should check out my ls swap.

[marvgarr68]

It's not the wiring that's the problem its making the components last.
Posted via Mobile Device

[NastyBuzzard]

Originally Posted by marvgarr68

It's not the wiring that's the problem its making the components last.
Posted via Mobile Device

Now that is a true concern.. That's one of the main points of going to diesel, longevity.

[NastyBuzzard]

I "fixed" the front end today. I just put a new sleeve on there and got the old broken one off. The long tie rod that spans from one side of the next is bent pretty bad and will need to be replaced.

I put some gas in and it fired right up, the engine and trans seem to be in pretty great shape considering.

The bed was a pain to get off as well as the front and rear bumpers. I broke 2 3/8" drive ratchets and one 1/2-3/8" adapters. Almost every bolt needed a cheater bar and some wouldn't give and had to be cut and some just sheared right off.

Here are a few pics.





It appears it sits about 6" higher than the 2wd 3/4 ton crew.





That is a pretty tough hitch, it will get re-used.



Is that block stock? Seems so b/c it would be where the bump stop hits.



Here is some thin metal...





Drivers Side shock mount



Drivers side frame rail



Some pitting only on drivers side.



So seems like a good bit of metal to replace, oh well. I am going short bed anyways.

[NastyBuzzard]

I really hate rust... So much to fix.





This was fun though.









It is amazing what you can do by yourself with just a few tools.

This is a measurement pulled on the widest part of the frame of the 1 ton.



This is a measurement pulled on the widest part of the frame on my 3/4 ton Crew.



It is amazing how much better the 88 frame looks.

I covered up the engine since it and the trans are still good. Hope to sell them soon.



So my plan is to use the front frame of the 78 1 ton 4x4 and just use the rear of the 88 frame that isn't rusted at all. Then use a blazer tank in the rear. Still converting it to short bed. Anyone see an issue with 1 ton front frame and 3/4 ton frame rear?

Progress will probably stop for a while due to how difficult it is for me to get my buddy over to fix all those wallowed out body mount holes so I can mount the decent cab on.

[NastyBuzzard]

The more I look at the frame on the 78, the less likely I feel like I will be using it. It may be a better option to swap it onto the 88 frame which still looks like new with the chalk marks on it from the factory and even the factory paint still on it.

Plus I plan on putting a headgasket on the 88 tan crew and running that 350TBI setup while I build the diesel. I just need to decide if I will use the th350 trans from the 78 or try and find another route, I will definitely want some kind of overdrive trans.

Any real insight on just swapping the 4x4 stuff over to the 88 2wd frame? I know I can buy the front rad support 4x4 mounts from diy4x or lmc just trying to figure out what else will be a hassle.

[y5mgisi]

Subscribed. Will read the whole thread later!

[NastyBuzzard]

Originally Posted by y5mgisi

Subscribed. Will read the whole thread later!

Thanks! Hopefully this one wont be as much work as the 87... It has kind of snowballed into doing every damn modification I can think of to make it somewhat unique.