Crew Cab Conversion

[1HI4x4]

I have an 86 K20 Big Block, 4 Speed, Single cab, Long bed. I am considering converting to a Crew Cab, Short Bed. Anyone done this? I'll be making new fuel tanks out of aluminum. I have already located a donor cab, and bed. Anything I need to know, to save some cash or time?

[okuma]

LOL.
i.m.o. to save some cash you are better of buying yourself an complete crew cab truck! 

[Blazin]

Conversion, and save cash sign me up! Get the whole crew cab truck instead of just the cab and shorten it. Still allot of work but probably not as much as fitting it to the regular cab frame.

[levisjohnson]

Plus the regular cab frame will be too short.

[Captkaos]

As levis said, Unless you don't care about a Bed, the LWB frame will be too small, and the rear kickup for the bed will require modification to mount it.

[1HI4x4]

I realize the frame will have to be stretched, I already have that part covered. I will use a section of original frame to do that with, and the guy doing the welding has stretched many semi frames so I feel confident we will be OK. I feel it will be easier to stretch the frame than to bolt all my running gear up to another frame, if I use an original long wheelbase frame it would have to be cut down for the short bed, so using mine makes more sense. The donor cab is from the same year truck, only problem is it was an automatic, mine is a 4 speed, looks like I will have to remove my pedals, but it is a slave cylinder so at least there is not alot of linkage. The donor cab is also a 2 wheel drive, so it's a low hump trans tunnel, the truck has a 3" body lift so I think everything will clear. I haven't bought anything yet but I can buy the cab, doors and bed for under $900 the cab needs no work, the bed needs one gas door fixed. Just throwing this out there for ideas.

This is not my first endevor in building a vehicle, I have a few street rods under my belt. I have been driving new trucks(crew cabs) for the last 12-15 years, but know I have a company car so I bought this older truck and love it, but I need more room. The truck has 4:56 gears with lockers front and rear, riding on 35's for now, they are to small for the gear in the truck(screaming it at 65 mph) so I intend on putting a set of 38's under it while converting the crew cab.

[levisjohnson]

Make sure you add the section of the Crew cab frame that has the cab mounts for the rear of the cab or you will have to cut them from the donor frame and weld them.  I have done both lengthen and shorten a frame (not on these trucks) and I feel it is easier to move the running gear over.  Especially if you have everything off already.  Just measure...remeasure...and measure again.  And right before you cut anything...measure it.  Either way, you are doing some major mods.

[choptop]

Really think seriously about finding a crewcab frame. It will be easier to shorten it, than stretch it, plus the added cab mounts and braces. Vile has shortend his longbed, so he can answer any question/ If you shorten a fram, you have one splice on each side of the frame, if you stretch, you will have 2 on each side. This doubles you chance for a failure, Not saying your welder doesnt have the experience or knowledge, but not many can understand the metalurgy on a 20+ year old frame. Before you go through the stretch, look around junk yard for a frame. You can probably find one with the suspension already on it for little money. People want shortbed frames, not longbed,crewcab frames. May even getit for the cost of junk iron.

[Captkaos]

It is far easier to cut 14" out of the wheelbase than it would be to add 19" especially since the part you need to add is under the cab not behind it..

[1HI4x4]

I guess I ought to clarify, I have ditched the 86, because I found a nice CC, and now I am cutting down a 1991 CC 4x4 V3500, installing a SWB and replacing the dual tanks with a 25G blazer tank. Plus repainting the whole truck.

Got the bed off this weekend and started the tank relocation, already ran into the first issue. Looking at Captn's blazer tank install, his shocks are outside the frame, my truck is a one ton 4x4 and the right side shock is leaning towards the rear behind the axle. It will have to be moved to allow the blazer tank install. I'm going to match it up with the drivers side, leaning forward in front of rear axle. If this is my biggest problem during this proccess then it will be OK.

 

[fitz]

  How did you make out with the shocks? If you get in a jam this may work for you. This pic is of a cab+chassis dually rear mounted in a 3/4 ton frame. See the outer 2 shock mounts? They are mounted to the top of the spring plate by welding on a grade 8 bolt to it.
  You would have to change your spring plates to this type of set up (1 tons are different). Just figured I'd run the idea by you.
  Good luck with the project. I can't wait to see pics of it.

[1HI4x4]

I got the Blazer tank in tonight, I will be moving the shock tomorrow. Fitz looks like the angled shocks on your rear are useing the stock shock mounts that have been moved to the top of the axle, that's pretty sweet. I already have the new shocks so the length will be off if I do anything crazy with the mounts, so I'm just going to put it in front of the rear at the same angle as the other one. Thanks for the suggestions though. We are going to cut the 14" out of the frame over the weekend, I have already wacked the 6" off the rear.

[1HI4x4]

I got the shock mount moved and the frame cut down today, the body shop that is going to prep it for paint has the bed done already, I'm taking them the truck tonight. Hopefully I will be spraying some paint in the next week.

[1HI4x4]

Here's the re-located tank

[Whitfield]

 


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