73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Body, Glass & Paint => Topic started by: tpull123 on May 01, 2011, 11:44:04 am
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everyone, new to the sight here and figured no better place for some help. For the past 10 months I have been pouring my time and money into this ground up Cummins Chevy build. Finally seeing the light at the end of the tunnel and I am hitting a small road block.
Its a 1978 3/4 frame.....that has had 2" added to the bottom of it to make it a 1-ton frame. The cab is a 85 as well as the front clip and core support. The cab is on the frame with a 1.5" body lift for drive train clearance, but in order for the core support to come close I need a 3" lifter under it. All the mount bushings are for a 78. Also it seems like the bottom of the core support needs moved back about 1/2" to 3/4" for everything to line up. I painted up the core support and front fenders only to have trouble with instalation. The cab seems to be leaning to the drivers side and the core support leans to the passenger side.....
This has lead to alot of frustation......any input is greatly appreciated. I included a few pictures to show the differences required in body lift to even get things close.
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Here are some more pics... More pics availabe if needed if it help gets an answer. I have read mixed things....some say it should bolt right on, others say the core support mounts need to be moved. Since its a 4wd, cant easily move the mount on the frame since its integrated with the leaf spring mounts.
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there is a post in the tech section about this http://forum.73-87chevytrucks.com/smforum/index.php?topic=9070.0 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=9070.0) i think all you have to do is cut the frame and it should work ok. are your body bushings new or used?
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so....if i read it correctly, you have a 1.5 inch cab body lift, but your core support is 3 inches....
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so....if i read it correctly, you have a 1.5 inch cab body lift, but your core support is 3 inches....
Same question ? Did you modified the frame somehow ? I don't understand why 1.5 on cab and 3 on front radiator support.
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@ 79Chevykid, I did read this post and thats where I saw mention of moving the mounts back which is what I thouht needed to happen based on my test fitting. But that was on a 2wd vehicle, since mine is 4wd, the mount position is fixed due to the leaf springs and coresponding brackets. I thought about making a custom mount/bushing that would take care of the offset since I can't move the mount its self.
Yes, I have a 1.5" under the cab, and the core support is requiring a 2.5-3" spacer in order to line up which is boggling my mind too, everywhere else I see, including the link posted by 79Chevy kid doesnt seem to need the additional body lift.
The other issue I am dealing with is my cab seems to be sitting slightly cocked to the drivers side. I have been measuring and measuring and cant track it down. Even tried different spot in the garage floor to make sure it wasnt that throwing it off. The only thing I can come up with the additional weight of the tank, and steering componets is making it sag just a bit???
I am ok with all the custom work involved with this conversion, but the things that should bolt up and dont get frustrating real quick. Any thoughts guys? This is my first frame off build, so never had any of these issues luckily until now.
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Oh, and yes....all the body mounts and core support mounts are in the factory location for a 78 frame. No modifications to any of those points of the frame
And the mounts are aftermarket polyurathane for a 78, they were used but in great shape and all matching.
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i see what your talking about with the leaf spring mount being there. you could probably cut just the core support mount off and leave the leaf mount there and re weld a new mount in the correct location. so no cutting the frame.
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I think I am gonna modify the bushings so it sits back about a 1/4" further and everything will bolt up. I still can't explain why I need an extra 1.5" of lift under the core support. Guess this is the punishment I get for not starting with a complete truck.
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Ok, so may have just figured out why front is having to be thicker.....on the 78 frames....did they use 2 bodymounts under the rear of the cab?? Or what I am saying is the 78's rear cab mount thicker than the front cab mount? Because right now I have them the same thickness and the front of the cab maybe pointed up....
Anyone with a 78 chevy want to chime in?
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im pretty sure the rear mounts are bigger. i looked it up and you can tell they're bigger. did you ever figure out what was wrong with your steering? i cant wait for more videos. good luck and keep up the good work.
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Finally got some measurements, and yes....the rears are taller. I believe it uses two body mounts under the rear (explains the extra set of Poly bushings!!). Havent tried too much on the steering, I put the 33's on it and it seems to turn much easier by hand, havent tried it with the motor running. Will get to that in a week or two.