swapping frame question

[beastman]

My dad and I are working on a 70 sweptline for when I turn 16, hopefully it will be done by then.....It is a long box and I want a short box, using an old stepside bed we have. In doing this, my dad wants to put this all on a 85 dodge sb frame...is this possible to do and would there be any other obstacles besides body mounts and steering linkage to keep from using the 85 frame versus trying to marry the 2 together? My dad, just feels that swapping frames would make a safer rig for me.
Thanks in advance for any advice.

JJ

[nfury8]

Welcome JJ! Always exciting to see a younger generation getting involved!

Is it possible? Sure! Your ability and skill will play a lot into the project. Isn't going to
be a direct bolt on. The Utiline (step side) bed may make things a bit easier though,
since that box was used from the 50's into the 80's with very little change.
As for safety, the only real advantage is going to be disk brakes, and steering, which
can all be added to the original Sweptline. I am guessing it is a D series? So you would
also pick up an independent front suspension, verses the straight axle.

There have been several similar projects done here and a few in progress I believe.

[beastman]

Thanks. My dad has decent experience in working on rigs. He's restoring a 62 plymouth savoy and has done his 70 challenger. He's not new to doing rigs. But hasn't done a frame swap..... He read an article on here about marrying two frames, but he was wondering if it would be easier to just swap them vs. marrying and if there would be any real obstacles besides body mounts and steering linkage.

JJ

[712edf]

Not really mentioning things as obstacles, but things to consider. I'd use as much from the 70 as possible when it comes to wiring, radiator, etc. If both are autos then you'd probably need to use the 85 shifter linkage since I believe using the 85 column would be the easiest route. 85 has the steering box ahead of the front wheel. 70 has the steering box behind, so angle will be different. If both trucks are manual tranny then maybe use clutch set-up from the 70.

You can have in-cab gas tank (70), on the frame tank (85), or both.

For safety/simplicity I'd use the 85 master cylinder & booster mounted to the 70 firewall. May have to do some fab work in hooking up parking brake, no biggie.

In some parts of the country, such a frame/body swap causes legal problems to arise (registration). Here (TX) it'd just still be a 70.

This is a good swap. You gain handling/braking and keep the clean look of a 70.

Bucky

[beastman]

Thanks, both are manuals. both d series....I appreciate the tips and advice...I think that is some useful ideas and we will use them. Im sure I will have more questions as we go on. Have a great day.
JJ

[65alive]

I agree with nfury8,

I married my frames, and I'm not sure if I'd do it again if given the chance. A LOT of work is an understatement, I'm not sure if the benefits gained are worth all the work. If I had it to do over, I'd use the scarebird front disc swap and tighten (freshen up) the stock steering. Welding the frames together was easy, rigging up the steering colum and reworking the cab mounts took a lot of patience to make it turn out right. I do like the parts avalibility of the newer front end, and it does ride nice, but without a sway bar, the handling around corners is about the same as the front leaf setup.

[soopernaut]

I'm in the middle of a frame splice myself. I had originally planned on doing a frame swap. The bed fitment was a big issue but I have a wide bed and it sits on the frame differently than the bed you are using. The conclusion was that there would be a lot more work involved in getting the bed to sit correctly on the newer frame. I had the bed on the newer frame and could see that I would have to make new mounts and flip some crossmembers. The biggest issue is that the newer frame sticks up higher over the rear axle, this means that the frame or the bed would have to be modified to make it sit properly unless you want everything to sit on blocks 3 inches higher than it needs to be. With your bed this might not be an issue because, like Nfury8 said, they used the same Utiline bed through 85. It is possible that the mounts were changed over the years though. The next biggest issue will be the steering but you'll have that no matter which route you take.

[beastman]

We are finding the bed not wanting to sit right..my dad said it seems to be bent a little...And it does sit higher than I want..Gonna have to fix that.......but, in all I am very excited to be doing this, I am 14 and I have time to get it the way I want, or at least close too..love these trucks. Can't wait til it's done.
JJ

[ufo]

It's going to at least look like it's sitting higher because the inside depth of the old truck box is 1inch deeper.
And I do believe someone here mentioned that the kick up over the axle is different as well.
Never attempted this swap just going by what I have read lately.

[beastman]

i have bigger wheels and tires for it. i want to lower the truck to, but that depends on $$$. have to use the steering coloumn out of 70 because of the ignition placement. i also have to cut a hole in the floor pans for a 4 speed tranny im using out of the 85. do you guys know if i can just cut the mounts off the 70 chassis and welnd them on the 85?

thanks jj

[beastman]

the utaline bed is an 82. the rear bed mount is a little bent. nothin we cant fix

[65alive]

I used the swepty mounts in my swap, but I had to lenghten them for the mount holes in the body to line up.

[beastman]

how much did u have 2 lengthen them? and how far off were they from the 85 mount spots?

[nfury8]

Very possible the mounts are in different spots, they are on the Sweptlines.
The profile of the Swept frames are the same between the 2 boxes, although
mounts are slightly different and the Uti frame is bobbed about 6 inches
compared to the short Swept frame. Easy modifications.

[beastman]

so far i have replaced passenger side floor pans and got rear of cab mounted. I have to lengthen the front mounts but after floor pans are done. steering linkage will be easy, need to make core support mounts, trim up inner fenders, and lower the truck. Does anybody know if my 318 will just drop in, mounts look to be the same as 70, 85 was a /6.