ExtendaCab Pickup - how far forward can I move the rear axle?

[jtice]

I am planning a truggy project for next year, and have been racking my brain with some ideas, figuring out which route I want to go.
I know that I want to start out with a V6, do a SAS, dual cases, exo-cage, and fab a flatbed for it.

Here is something I have been thinking about, that I need to know if I can do or not, before I get my hopes up. haha
I would like to use an extended cab pickup, cuz I like having a bit more internal storage, and the ability to haul a couple more passengers if I had to.
But, I like the wheelbase of the standard cab truck better.
Standard Cab= 103.3" Extended Cab= 122.5"
So, I was thinking of getting an extended cab pickup, and moving the rear axle forward as much as I can.
I am hoping to basically just more the spring hangers forward, and shorten the driveshaft of corse. Would rather not cut the frame to shorten it. Though I will be cutting any extra frame that hangs off the back past the rear spring hangers.
Was planning on the flatbed hanging about 6" or so out past the rear spring hangers.
So, how far forward do you think I can more it? What would stop me, or what other issues do you see me having.
Any tips or advice would greatly be appreciated.

 

[KLF]

Better setup: get a SWB truck (reg cab, short bed), swap an extra cab on it. Wheeled with a guy once (Andy Zook) that did this, it was a nice setup. He also had a Supra engine under the hood.

 

[jtice]

I have heard of that done, but I have two issues with that.
It seems like that would be a much more costly solution, I doubt I have access to getting a whole other cab like that. Then I know my luck, and I would never be able to sell the left over standard cab.
I also see that being ALOT more work.
Dont get me wrong, I am not looking for a total lazy half assed way to do this, it just seems like it would be a nice option to simply move the rear axle forward.

 

[KLF]

Well, you certainly aren't gonna be able to move it forward ~9". Better off to just lop off the whole rear of the frame, do a 4-link setup.

 

[4WheelUnderground]

Couple months ago, 4WD Toyota Owner mad did a story on a truck that they swaped the bed out from the Standard to a Longbed. I think that truck now sits at 112".

 

[Bogo]

The main issue is getting enough clearance for the axle to move up and down. If you are lifting the truck then that may provide some of what you need, but I doubt it would provide all of what you need. Find a copy of the FSM for the truck you get, and look at the body mechanical section and compare frames. I know the '93 pickup FSM on the web has the frame dimensions and drawings in it. There is a slope in the frame from just in front of the front leaf spring mounting point to just in front of the axle. That area needs to be moved forward and or steepened to have enough clearance for the axle to move properly. In some ways it would be easiest to cut a section out and make a section to jog it up much faster. You would need to do the engineering for that. Also it will take jigs to make sure you weld it back together in proper alignment. This is the reason using a short wheelbase frame is possibly easier. It all depends on your skills and tools.

Look in the "Body Mechanical" section: 1993 Toyota Pickup Service Manual
The previous two generations of pickups aren't really all that much different. Just minor tweaks here and there.

As for how much to remove, as much as needed so you can use a standard short wheelbase drive shaft. Might as well make it so standard parts can be used. With lifting, that will be just a bit more removed than the wheelbase difference between short and extended cab trucks.

 

[jtice]

Thanks guys, looking over things, it does seem that the frame clearance might indeed be the biggest issue.
I figured I couldnt get it to the 103" wheelbase, the cab itself would get in the way by then I think, but I still would like to shorten it as much as possible.
I got he prints of the frame dimension, thanks, I will have to study them and see what numbers I can come up with.