1 ton k30 conversion

[72chevfan]

Hi guys I have a 1978 K30 4x41 ton regular cab dually that the body is trashed and am thinking of converting it to a flatbed and using a 1972 AC cab.I want to use the '78 frame, running gear, steering and possibly the brake system. What problems will I encounter? Has anyone done this before? It seems to me that since the frame is already set up for the running gear, that body mounts and steering will be my biggest challenges. What do you think? Thanks

[special-K]

Alot of guys have done it.There`s not alot to it.The cab needs about an inch or two of lift toline up with bed.But,with a flatbed I guess that dowsn`t matter.The radiator support will need mounts moved or drill throgh frame and rig some bushings.

[72chevfan]

Thanks for the feed back Special-K . I'll post pics as I progress

[Yukon Jack]

This will be a good project to watch.

[72chevfan]

Thanks Yukon Jack, I was thinking of going a big block but after reviewng the problems that you encountered i may rethink my options. Any other advice on my swap out is appreciated

[rambler]

Looking forward to watching this thread.. so would this be titled a 78 K30? or a 72? hmmmm...

[Yukon Jack]

Heck with doing a body swap you might be able to address the firewall issue by just mounting the cab back a little to give you the needed clearance. That and a little body lift that you could build into the body mounts might be a good solution.

[72chevfan]

Rambler I have given a little thought to that issue and am leaning towards keeping it a 72, to avoid stricter emission testing, even though right now where I live it is not required but who knows about the future.Also I'll have to check with the state patrol for the legal requirments. Should be no problem since I have both titles.

[ed2552]

sounds cool, keep us posted and we LOVE pics, so if you don't have one, get a digital camera, good way to remember how stuff goes back together as well

[72chevfan]

Yukon Jack good thought on the body placement.Once I get the old body off I'll fit the "new" 72 cab and front-end on it. Was it you that mentioned on your site that an additional 2" is required to accomodate firewall clearances when installing a big block

[72chevfan]

Ed I do plan on taking pictures as this developes and will post at a later date

[MrBeast]

Your best bet here is going to be to stick with the 72 frame, it will be much less work to swap the 1 ton axles and T-case into your 72 than it will be to set the 72 cab on the 78 chasis, While you have your truck apart setting up the spring hangers, then would be the time to adjust your engine location, you can do so simply by removing the rivits or bolts in your frame that hold the engine cross member in place, sliding it forward to the desired location, measuring the difference, re drilling the holes in the appropriate position, and then put some grade 8 bolts in the holes.

[MrBeast]

Oh, and if memory serves, the spring perches on your front axle will be the same width as a 67-72, but the rear axle will need to have the perches moved, it is not a difficult process, I have done it a few times. Just make sure you are dead on with your measurements.

[rambler]

Originally Posted by 72chevfan

Rambler I have given a little thought to that issue and am leaning towards keeping it a 72, to avoid stricter emission testing, even though right now where I live it is not required but who knows about the future.Also I'll have to check with the state patrol for the legal requirments. Should be no problem since I have both titles.

i would lean to the 72 as well, if you keep it as a 78, you will have to post on the OTHER board... J/K

[Yukon Jack]

Actually, the spring perches on a 1 ton rear axle are in the correct location. The 3/4 ton rear axles need the spring perches moved.

A 2" body lift can help, but it really depends on your particular truck. There are a number of people on this board who have put a bbc into their 4x4 with no clearance issues, while others have trouble. I'm in the process right now of moving my motor forward so I can have my body lift reduced to 1" to 2". There are a number of posts in the 4x4 suforum on swapping in a bbc and what trouble certain board members have had.

Here is a good link to one on that subject.

[72chevfan]

MrBeast I have considered staying with a factory 1972 1 ton and doing the running gear swap out. In fact, I presently own a running C-30 Chevy flatbed with a factory big block and a GMC C-30(no motor) factory big block that was a chasis mount camper originally. Then I came across the 78 4x4 for the right price. I am considering all of my options. The nice thing about my plan is that I have a couple of options and can visually view all of the trucks which will allow me to figure out the best way to go. Thanks for your input.

[72chevfan]

Thanks for the info and the link Yukon Jack.I'll check it out.

[MrBeast]

Originally Posted by 72chevfan

MrBeast I have considered staying with a factory 1972 1 ton and doing the running gear swap out. In fact, I presently own a running C-30 Chevy flatbed with a factory big block and a GMC C-30(no motor) factory big block that was a chasis mount camper originally. Then I came across the 78 4x4 for the right price. I am considering all of my options. The nice thing about my plan is that I have a couple of options and can visually view all of the trucks which will allow me to figure out the best way to go. Thanks for your input.

You are welcome, just a thought but you really need to post some pics!

[JustinR]

I am currently installing a 1970 Cab off a c30 on a 1990 K30 dually chassis. I opted changing the bodies, instead of mounting the transfer case and front axle on the 2wd frame. I just thought with the skills I have I would be better off not doing driveline mods. So far it is all going really well. I installed the body mounts off the 1970 chassis on the 1990 frame. The frame widths was 1/8th of an inch different with the 1970 to the 1990. So all I had to do was get all the spacing right, then drill holes for the mounts. The steering wasn't a big deal either, I had to drill out the plastic rivets in the steering shaft, but after that I could use the 1970 steering shaft. The one problem I am trying to figure out is the rad support. The Rad is larger on the 1990 chassis so that center opening in the 1970 rad support won't work.

I have a build thread link in my sig.

[72chevfan]

Thanks for the input and build link JustinR. Does it look like the cab will allow the use of the 1990 factory gas tanks? Have you solved your radiator issue?

[72chevfan]

MrBeast I'll try to post some pictures of all my trucks soon.