79 chevy truck frame on 56 truck project need help

[slownlow]

ok i have just acquired a 1979 chevy truck long bed rolling chassis.... my thought are to retro the truck ...i need to know is how hard would it be to mount a 56 cab on a 79 frame and is it harder to find a long bed for the 56 or should i chop the frame down to a short bed all thoughts and comments would be helpful

[tiggerstoy]

i have a 77 chevy stepside shoty, i was thinking of doing just what your thinking of doing.....cuting the frame to make it short is not that hard, my 55 was a long box, good stands, good sence, patience,and a good welder, and away you go...it's more than that, but you get the drift of it....good luck, and take lot's of pics.....max.

[1-ton of fun]

if you are buying new bed sides, then they are no harder to find short or long. i am keeping my 4 headlights and my long bed!

[jkaylor68gmc]

I used a '65 C-10 frame under my '47. I had to get my bed cut down 13-inches and built a square frame in the bed for it.

[slownlow]

thats great news then if the frame will work ....now my next step is to find a cab ....i should be able to buy all the peices to make the bed ..at least i think s i can .... now what would be my better bet .....
a long bed or short ...becuase i might be able to get my ands on a short bed frame?
thanks for your help

[56hotrodred]

I am currently early into a project that is placing a 56 1/2 ton SWB body onto an 80 1/2 ton SWB frame.

I am not going to do any frame shortening but the space between the cab and box will end up about 3 inches. Actually does not look too bad but if one wanted to shorten the frame it would not be too difficult with a good welder.

The same would go for the long frame you are talking about. There are some spacers required for the front cab mounts as the frame drops about 4 inches and some fabfrication for the fron rad support but these have been pretty easy to work out. I have the body sitting now on the old cab mounts that are clamped to the frame. i hope to be able to pull the cab soon, take a few more measurements and hopefully weld the old cab mounts on to the newer frame.

Barry

[slownlow]

ok everyone ...well i finally have the chassis sitting in my drive way ...now i need to find a cab ...so if anyone knows where one is sitting .....im not looking to pay alot of money for just a cab ...but let me know ....i want to be able to mount the cab on this 79 chassis before i start to build my street rod
thanks alot guys

[ezekiel]

Hey Guys,

While I was researching this topic myself, I found these photos of a 56 chev truck on a 79 frame. Maybe you could talk to this guy for more info??

Check them out here.

[buds56]

I just got my truck legal about a month ago and it drives great.the frame is a 79 shortbed that was rolled over but it had a new 305 and 350 turbo. I used the 56 framemounts on the new frame. A 4" spacer is needed for the front mounts. The front narrows about 4 inches and the steering box made the rad support the hardest part of the job. I bought a 67 firebird radiator [crossflow with side mounting brackets and short] and modified the support till it fit. I had my cab floating over the frame with the fenders on with a couple bolts to make sure the tires are centered in the front wheelwells before I drilled the frame.I believe but can't remember exactly I got 1/2 to 1" of the wheel base difference here. You're going to have to cut the frame in the rear as my 56 truck originally was a long bed and the bed measured odd like 7' or 7'6. One of the downsides is you can't put a wide tire on without them sticking out. my truck is no showpiece but it sure is fun to drive and at about $4500 invested so far I'm pleased. I'm in the dreaded body work stage now and hopefully by spring it may have some paint. If I can help let me know. bud http://www.picturetrail.com/gallery/...69&uid=5978428

[56hotrodred]

Thanks for the reply.

I had viewed your pictures very early into my project about the time that I was trying to decide to do the swap or not. The photos and stance of your truck were instrumental in me making my mind up on which route to go.

I am working with an 80 SWB and am going to leave the frame alone. The gap between the cab and box is going to be about 3 inches and think I can live with that.

I am hoping to use the original rad support with a new aluminum rad & electric fan that pretty much bolts right into it. I was thinking on trying to go cross flow rad or not! My new fabricated rad supports onto frame are made up of some parts I got off another 80 4x4 and seem like they are going to work fine.

I just figured out that the firewall brake kit I got from International Chassis in Phoenix will tie right into my 80 frame/brake proportioning valve and brake lines with the purchase of one brass reducing fitting. This is a pretty easy swap. The rear bigger line screwed right into the master cylinder. That both surprised and pleased me. I think they said the booster and master cylinder were from an 85 F--d Ranger. It does not say F--d anywhere on it!!!

I should have the time soon to figure out how to post pictures on this and the chevytalk forum soon.

Bodywork is progressing slowly and piecemeal so far with doors in at body shop, tailgate and hood almost ready to go. Rear fenders need lots more sanding. My front fenders are the roughest body parts of all and I have not decided if I am going to try to buy new or fix these.

My winters main focus is going to be on frame and suspension. Probably helwig sway bars, new poly bushing all around. Not sure about lowering. It might be a little high but think I will wait on that. If anything I may get 2 1/2 lowering front spindles with new coils and drop the rear with new springs/shackle lowering kit to sit level. I have been wondering about wider tires on back but in light of your discussion will obviously have to look a little closer.

Again thanks for your response as it all helps.

Barry

[stellarmishap]

I have a 57 on a 71 4x4 chassis, bought it that way, soon will be tearing it apart to fix lots of little things, but it drives real nice. I know the frame was lengthened 12" or so, I could take more pix of any mounts if it would apply..

[magsnubby]

I've been kicking around doing a frame swap on my '58 step side. I thought about a Camero subframe or an aftermarket ifs. But since i'll be doing a frame off anyways, and it will be my DD and it will be used as a truck, i might just go with a frame swap. I can pick up a complete mid 70's to early 80's pick up really cheap almost any where. Right now a frame swap seems like the most viable option for me.

buds56,
i spent some time looking over your pictures also and like 56hotrodred, they pretty much helped me make my decision.

In some of the construction pictures it looks to be sitting pretty high. Did you lower it any, and is so how much? Looks like the front could go just a tad lower? On the tire and rim combo, what width rim and size tire do you think would work and still look okay?

I'll most likely be running some type of ww with these:

https://www.mooneyesusa.com/Store/pr...ad59e3bd5e3a2b

Or these:

https://www.mooneyesusa.com/Store/pr...ad59e3bd5e3a2b

Good info on your truck there 56. Looking forward to seeing so pics.

[56hotrodred]

In looking at pictures of others who have put older bodies on later frames and in looking at how mine is sitting right now (held together by vice grips & clamps only) I have thought that some and now mine is/are a little high.

My truck is currently sitting on 235 75R/15 (stock for the 1980 frame they came on I think). I am hoping to widen the rear tires some and maybe mini-tub the box to facilitate this if I have to. To widen rear tires without hitting fenders it might require some sort of offset rim thus the mini-tubs. Not too sure about this yet but I do like the look.

I am planning to replace all springs (coils in front & leafs in back) and put in polyurethane bushings everywhere with front & rear sway bars. All other fittings (tie rods, upper & lower bushings, etc.) will also get changed. I figure that I might put 2 to 2 1/2 front spindle drop and combination rear leaf/shackle drop in rear. By using spindle drops you change no front end geometry. The rear drop will be designed to level it out and may be between 2 & 4 inches.

This will not slam the truck as this is not the look I am after but should get it to a nice ride height allowing the suspension to be better than stock.

In reading other posts and looking at pictures about people using later chevy truck frames with torsion bar front ends there is another whole realm of possibilities. For me the 80 frame was inexpensive and available. I have ridden in enough of them - even 2 x4's with short wheelbases - over the years and know that one can get a good ride.

[56hotrodred]

This post is meant for slownlow.

In re-reading the posts under this topic I just wanted to make a quick comment on yours. In order to make your swap as painless as possible you may want to look for the 4 cab mounts that attach to an old frame to sit your cab on. I am not sure if they are available from aftermarket suppliers because I had a set on my old frame to remove and use. This would help in placement of the old cab on the newer frame otherwise you will have to fabricate them. Not impossible I would imagine but way easier to use some old ones. I currently have mine clamped onto the 80 frame and bolted into the 56 cab. 80 frame is correct width at 56 cab mounting points and as soon as I am sure of location I want I will bolt and/or weld cab mounting brackets in place. This is just a little uncertain right now as I may be able to move the whole works back a little farther to close the gap between the cab and box currently measured at about 3 inches. The problem being the steering box and my new front rad support. I have to spend some time out there and look at it more to figure it out. The 3 inch gap is really not too bad and anybody who has looked at it ahs not even noticed it until I said something.

[buds56]

Alot of the pics in the garage there were stands under the frame, but yes it still sits to high. I plan to put some 2 or 2 1/2" drop spindles in the front. I put 2" drop in the rear [longer shackles]. Before I drop the front I need to get the truck to sit straight . I believe the left rear spring is weak but it needs more investigation. The wheels are 15x7 daisies with 235/75-15 rear and 225/75 in the front.

And the rad support was the hardest part of the job with the steering box in the way. I'd like to see your pics as you progress with your trucks,especally around the radiator as mine was pretty crude. thanks ,bud

[tiggerstoy]

well, i was bored this weekend, so i made up my mind to do the 77 to 55 swap, i have some thoughts on the firewall, and rad support area's that mite make life easy, but if not, i still have 2 spare cabs, this is to be a daily driver when done, and it's not a costomers truck, so i mite cut a corner ot 2...lolthe 77 already has a 350 4 bolt, and a 700r4, i have added the newer hallogen lights to the 55 tubs, and i plan to use all the 77 wire harness.....i think i'll use some of the 77 fire wall, im doing the measurments on all of it now before i get cutting....i'll post pics in a day or 2 after i get some more done....max.

[slownlow]

what do you plan to do with the extra cabs?????.....in search of a cab
thanks slownlow

[tiggerstoy]

slownlow, p.m sent....max.

[blazins10]

i know this tread is older but im doing this swap on my 55 , can someone give me the measurements from the front leaf spring hanger to the back cab mount ? i wanna check mine to some elses also im shortening the frame to make up for the longer frame 3.5 inches ,does everyone have some more pics about this swap thanks mike

[burntove]

I am mounting '59 short bed on a '76 short bed frame. I z-cut 4 1/4" out of the frame where it flattens out under the cab,and welded it up with fish plates on the outside and boxed it in.I also cut some off the front of the frame,back to where the steering gear front bolt is.For me, I wanted to have some room between the firewall and the HEI distributor,so I mounted the engine and trans and then set the cab where I wanted and made my own cab mounts. I then set the bed so it was centered in the wheel wells and measured from the front of the bed to the cab and that gave me the 4 1/4" to cut out of the frame.The front clip ended up centered in the front wheel well like it was made that way.

[blackdiesel]

I got what u need. Just pulled my fifty seven off a 77 swb 4x4 frame. I'm going more hot rod 2wd style now, its ready to bolt on another body and roll...

[blazins10]

mines going be a frame dragger on 22s , the factory wheel base for a 55-59 trucks is 114 and the 1973-1987 sw trucks are 117.5 so i cut out the dip in the frame under the 78 cab and replaced it with 2 by 6 box tube and used the factory 55 frame cab mounts and shortened it in the process havent got the cab back on yet but hopefully this weekend

[L-Diablo]

i know this thread is old but i was wondering what where the mesurements from the leaf spring mount to the back of the rear cab mount , im doing a 1959 apache fleetside

[OrrieG]

Look at the manual link in my signature. In that document there are stock dimensions that show the relationship of the cab mounts to frame and axle mounting points. The same information is shown in the factory assembly manual.