54 Frame Shortening Question

[mavdog32]

Ok since this is my first post Ill start with a little bit of info on where this build is going. End stats are as follows:
- 54 Chevy 3 window
- 5.3 forged w/ precision 7675 Turbo. Already at the machine shop
- Built 4L60E
- C4 vette axles w/ D44 rear
- Gunmetal w/ all chrome blacked out.





Ok I bought a 54 Chevy truck with a ghetto Z frame job done already to a 3600 frame(Has a great body!). I am having a hell of a time finding another 1/2 ton frame but finally came across a 1/2 ton GMC frame but its the 125" wheelbase frame and my bed is for the 116" wheel base frame. I have no problems with shortening the frame but I am not sure how to do so since the frame angles out the whole way back. I need to pull about 9 inches out. Any suggestions, pictures, etc.. that you have will be much appreciated.



Also looking at whether I should run bags or coil overs. I dont mind the extra equipment that goes with bags but I am not sure how well they work for the night at the strip. I like the adjustability though. FWIW 95% of the time I will be driving it around town and to work.

[mr48chev]

This should be the same as the one you are looking at. The extra length which I believe is 9-1/4 inches is added where the extra crossmember goes across.
This is the GMC frame that I am going to put a Chevy front crossmember in and use under my rebuild when I stretch the cab.


You will also have to change the front crossmember over to the Chevy crossmember that you should be able to take out of the old frame if it is ok.

This drawing was done by one of the guys over in the 67/72 section so you won't be able to use the measurements and will have to substitute the differences in wheel base on the trucks you are working with. The overlap gives a lot stronger joint than just cutting the frame off square and butt welding it back together.

[chebyshortbox65]

I cut that xmember out with the park brake setup shortened mine right there works perfect I also took out the rear x member and pinched the frame for more tire clearence
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[mavdog32]

Ah cool thats a method I had not considered but obviously will work well, and be strong. Does the frame width difference become an issue when using this method, or do you just pull it out to line up, then weld? Also I know the length is different but should I still use the body mount holes as a reference?

I also thought about pinching the frame a bit but I need to check the kit for the c4 suspension to make sure narrowing doesnt affect it.

[mavdog32]

Would it make more sense to cut the frame in two different places and suck it in 4 1/2" ish on each one. Maybe I have the wrong idea of how much of an issue I am going to have with the angles of the frame.

[chebyshortbox65]

I actually cut the rear xmember out first and the frames not very sturdy at all then I cut the frame rails I have them tacked right now they lined right up I would cut it in one place I think the frame is strait under the cab the frame is strait I cut mine here so I could mock up the bed and everything before tearing it apart to finish weld the subframe I wanna set it on the ground all together make sure it sits where I want it I'm fish playing the cut section with a 14 " by 5" plate then I might box the frame haven't made my mind up yet and I also cut the frame like above so the top rail sits on the lower for more strength
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[mr48chev]

I'd cut it where the change in width is the least. Right at that crossmember is where they stretched it though. One thing though is that the holes for the cab mounts need to stay where they are at and not move so you need to make the cut behind them.

I'm not quite following you on the 4-1/2 and 4-1/2 but unless you are going to build one stout new X member or center crossmember piece I'd leave the crossmember that has the gussets on it and narrow the frame to straight right behind the gussets. Unless you are running really wide tires you most likely don't need to straighten the rails out though unless it just makes setting things for the rear end easier.

[mr48chev]

This is a chassis that Steve at Industrial Chassis in Phoenix is building on the new table he just finished. One probably doesn't need to be quite that stout as far as the x member goes but nothing is going to move on this chassis when it's done.

[mavdog32]

The cut like drawn above where he removed the 12", I am talking about doing that but only removing 4" then pulling out another 4 1/4" a little further down than that one so that its not all taken out of one section of frame and I wont have issues with frame with matching up.

As far as the width goes in the back, and pulling it in goes... I just need to make sure that the flat out engineering kit will work if I narrow the rails. I need to run as wide a tire as possible, the motor is going to be around 650-750 HP on pump gas and higher on race gas. I am running a boost controller to help with wheel spin but every inch of rubber on the ground helps!

[mavdog32]

Originally Posted by mr48chev

This is a chassis that Steve at Industrial Chassis in Phoenix is building on the new table he just finished. One probably doesn't need to be quite that stout as far as the x member goes but nothing is going to move on this chassis when it's done.

[mavdog32]

I was thinking about running a progressive cross member and plating in some of the frame as well. Hopefully it will be stiff enough but yea, it still wont compare to that frame above.

[mr48chev]

Not too many will stand up beside that one. It sounds like you are forming pretty good plans to have a solid truck.

[reinmeister1951]

I dropped in to visit Steve last month when I was in Phoenix, He had so much neet stuff going on that I don't even remember his chassis table.

[mavdog32]

Thanks, I will post up pics of what I have so far in a build thread. Come to think of it, I really havent taken many pics. Out of curiosity what does Steve charge for his frames? I built my rock crawler with an Advanced Frameworks Frame and it was the best thing I ever did in that build! That said I would like to go that route with the truck but all the frame I find are like 5K plus!

[mr48chev]

I don't have a clue as to what he charges for the frames like that. That photo was actually part of a thread he did on the HAMB detailing the building of the table the frame is setting on. The table is a work of art in it's self. Here is the link to his website http://www.industrialchassisinc.com/

[mavdog32]

Yea I saw the website. Not much about the frames on there though. Mostly IFS stuff, I was really impressed he did a DIY Mustang II thread since in reality that probably cuts into his business!

[mavdog32]

Hey one last question, since I am moving the crossmember over from the other frame and I am cutting the rivets to do so, what do I replace the rivets with?? Do I use bolts or should I just weld it in?
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[solidaxel]

Originally Posted by mavdog32

Hey one last question, since I am moving the crossmember over from the other frame and I am cutting the rivets to do so, what do I replace the rivets with?? Do I use bolts or should I just weld it in?
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Welcome from So Az.
I think I would do both AFTER you squared it all up
Here is a truck that we lengthened!
The spot we chose was right behind the rear cab mounts
This truck is currently in Co. Springs being finished up so we can get on the market for sale

[mavdog32]

That's freakin cool, you will have to let me see that before you all haul it out of town
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