Exact frame measurements needed for converting a longbox truck to shortbox

[russellrox]

was wondering if someone knows of the exact location and measurements needed to convert a longbox frame to a shortbox.

[ol_skool_chevy]

Exact?
Well, I can say 12" out of the front and 8" out of the rear....pretty simple

the 12" is taken from the frame under the cab...

[russellrox]

was looking for measurements on where to cut the step in the center , how much behind the rear cab mount, where is the reference point to measure back from.

Originally Posted by ol_skool_chevy

Exact?
Well, I can say 12" out of the front and 8" out of the rear....pretty simple

the 12" is taken from the frame under the cab...

[padresag]

you might find some pictures in the faq section
ron

[Lugnutz65]

Originally Posted by ol_skool_chevy

. . . . the 12" is taken from the frame under the cab...

Pardon me if I'm just not thinking, but removing 12" from the frame BENEATH the cab doesn't make sense. Longbed and shortbed trucks are identical from the rear of the cab forward. Right?

I'm thinking you meant remove 12" from behind the cab.

These threads might be helpful
http://67-72chevytrucks.com/vboard/s...d.php?t=499189

http://67-72chevytrucks.com/vboard/s...d.php?t=333241

http://67-72chevytrucks.com/vboard/s....php?p=4881959

http://67-72chevytrucks.com/vboard/s...d.php?t=123624

http://67-72chevytrucks.com/vboard/s...d.php?t=275426

[donthekawguy]

Originally Posted by Lugnutz65

Pardon me if I'm just not thinking, but removing 12" from the frame BENEATH the cab doesn't make sense. Longbed and shortbed trucks are identical from the rear of the cab forward. Right?

I'm thinking you meant remove 12" from behind the cab.

These threads might be helpful
http://67-72chevytrucks.com/vboard/s...d.php?t=499189

http://67-72chevytrucks.com/vboard/s...d.php?t=333241

http://67-72chevytrucks.com/vboard/s....php?p=4881959

http://67-72chevytrucks.com/vboard/s...d.php?t=123624

http://67-72chevytrucks.com/vboard/s...d.php?t=275426

You have to take it out from under the cab. There isn't enough frame to get it anywhere else. The 67-72 you can do it from behind the cab with the cab still on the truck.

[russellrox]

I have another decision to make lol, I have a perfect long box that is on the truck now, do I cut it down to a shortbox, or do I use my existing short box and do the rust repair and bodywork and sandblasting on it. The longbed has 25000 miles on it, original bed wood, in unreal original condition, my shortbed is dented up and has been previously patched at some point, I also have to replace the front panel, tubs, and tailgate. Not sure what is more expensive.

[argonaut]

Its not just the available length. Both long bed and short bed pickups have the same length trailing arms. So best place to remove the 12" is from the section of frame in front of the center crossmember that the trailing arms mount to. Then just relocate the rear cab mounts and the front bed mounts 12" back. Otherwise if you cut behind the cab mount, you'll need to shift the crossmember 12" forward.

Unless it is a 4x4 or a GMC with rear leafs. Then you can cut right behind the rear cab mount.

[Captainfab]

The best place to remove the 12" is under the cab. just a little ways forward of the rear cab mounts. This also allows you plenty of room for the reinforcement plate on the inside of the frame. Then you just have to move the rear cab mount brackets 12" back. And of course trim 8" off of the back of the frame.