Long Bed -----> Short Bed conversion questions

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Cree

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If I’m seeing it correctly, it’s showing all the wheelbases relative to each other. I marked the long bed and short bed. You can also see what lazybones was pointing out.
Yeah, I caught that part with the red. Thanks. I think I'm just gonna go to a yard with a tape. Without knowing what all the codes mean, I'm curious about a few of those measurements.
 

MrPink

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Which frame is that? Or are you telling me they're the same and you Chevy did what I'm thinking of doing but in reverse?
the top frame with the red markings is the regular cab long bed frame. the bottom on is showing driveline lengths.
If I’m seeing it correctly, it’s showing all the wheelbases relative to each other. I marked the long bed and short bed. You can also see what lazybones was pointing out.
Nope. And the markings are incorrect. the top one is crossmember locations for a C10903,20903,30903 all of which are long bed reg cab chassis. The bottom one shows different driveline combo's(The M RPO'S) and where their lengths end up.
 

Caman96

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the top frame with the red markings is the regular cab long bed frame. the bottom on is showing driveline lengths.

Nope. And the markings are incorrect. the top one is crossmember locations for a C10903,20903,30903 all of which are long bed reg cab chassis. The bottom one shows different driveline combo's(The M RPO'S) and where their lengths end up.
Mr Pink I did notice they were a little different than actual wheel base, but close enough to make point about differences. Was trying to show how frame narrows as lazybones pointed out. Close enough for Rock’n’Roll :Rock on:
 

Hipster

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If I’m seeing it correctly, it’s showing all the wheelbases relative to each other. I marked the long bed and short bed. You can also see what lazybones was pointing out.
Don't think so. They look like old school Chief frame equipment diagrams or similar. Top numbers are mm bottom are inches.

The first diagram. The length measurements are notating where key frame components or measurement points are located in reference to the front crossmember or front wheel centerline(???). This diagram is showing one frame with a 131.5 wheel base and that's it. The frame is shown with 2 section heights as well. There is usually a page that shows what all the diagrams encompass and only thing I can think is this is for all 131.5 frames 1500 and 2500 hd's etc. All the dimension listed(body mounts, wheelbase etc.) would be the same for both frames.

The second diagram shows all the width measurements from the vehicle centerline. It's showing a 21.34 measurement(center of the vehicle to center line of the frame just forward of the front bed mount to 17.05 at the tail end of the frame. 3.29 more narrow per side.

Imho both diagrams are working off of the rear side of the front crossmember. Chief, Blackhawk, Gm, all put out frame diagrams like this and this diagram is not what @MrPink thinks it is and why he believes the #'s are incorrect.

Thank God technology has improved and us collision guys aren't working off sheets like this any more. Taking frame measurements off a moving part such as a front spindle or front wheel centerline is not the way to do things.
 
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Caman96

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Don't think so. They look like old school Chief frame equipment diagrams or similar. Top numbers are mm bottom are inches.

The first diagram. The length measurements are notating where key frame components or measurement points are located in reference to the front crossmember or front wheel centerline(???). This diagram is showing one frame with a 131.5 wheel base and that's it. The frame is shown with 2 section heights as well. There is usually a page that shows what all the diagrams encompass and only thing I can think is this is for all 131.5 frames 1500 and 2500 hd's etc. All the dimension listed(body mounts, wheelbase etc.) would be the same for both frames.

The second diagram shows all the width measurements from the vehicle centerline. It's showing a 21.34 measurement(center of the vehicle to center line of the frame just forward of the front bed mount to 17.05 at the tail end of the frame. 3.29 more narrow per side.

Imho both diagrams are working off of the rear side of the front crossmember. Chief, Blackhawk, Gm, all put out frame diagrams like this and this diagram is not what @MrPink thinks it is and why he believes the #'s are incorrect.

Thank God technology has improved and us collision guys aren't working off sheets like this any more. Taking frame measurements off a moving part such as a front spindle or front wheel centerline is not the way to do things.
Mr Pink I did notice they were a little different than actual wheel base, but close enough to make point about differences
 

wiscomick

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So, I'll apologize up front and say I haven't read the full thread here, so you may have already gotten the answers you were looking for, but here goes anyway....

I had ALL the intentions in the world of doing this exact thing. So much so that I had my truck stripped, bought parts, the works. It really is pretty straightforward.

As far as the gas tank, if you've already got the small tank, you need to do nothing. Everything including the filler is where it needs to be. You're done there.

As far as the shock mounts, you will need to move them and fab up a little something to get them on the frame. I planned on just using angle iron. The shock mounts aren't in the same spots as the SWB, and the SWB mounts won't bolt up to the shortened LWB frame. There's a few guys on here that have done this conversion and in some of the pics you can see how they modified and welded the shock mounts up. Basic stuff honestly.

The biggest thing is moving the axle. If you'll notice in the threads you'll find on this - most guys that complete this conversion end up with trucks that are waaay high in the rear because they didn't take the geometry into account, they just moved hangers without thinking it through. To solve this, you have to use the 2" drop hangers that are available for the front of the leaf spring. It's really the only way to ensure that the front leaf spring mounting hole can be located in the proper place on the frame as it would be on a short bed frame. You simply can't just move that hanger forward and expect it not to lift the truck up.

I had this all planned out and was fully intent on executing it the right way as my truck too has sentimental value... until I found how thin my frame was from 25 years of Wisconsin's BS. I got wildly lucky and found a RCSB frame in Michigan that had very low miles and I ended up starting over from scratch - and am now building a RCSB truck from the ground up.

I've researched this conversion into oblivion and I would've loved to have done it but my RCLB frame just wasn't worth putting the time into. No matter what happened, that frame was gone. If I can help out, feel free to lmk.
 
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