Frame/chassis swap questions

[slotard]

I have a '73 C20 Camper Special. One of the things I really like about it is that here in CA, there's no smog testing (or any other sort of inspection) required for trucks '75 or older. Seeing as VIN is body rather than frame, a swap shouldn't change that.

If all goes well I'll be coming across some money before too long. Right now I have 350/350 with way too big of a carb (Edelbrock 750), 4.10 rear end, atrocious mileage, and not a great cruising speed on the freeway.

I'm thinking of looking for a damaged (body only) 99+ 3/4 or 1 ton, and swapping my cab/bed over, keeping the modern engine/tranny/suspension. Probably gas rather than diesel, unless I find the right deal on a DMAX. Obviously I'll have some electrical fun, I'm expecting that.

My question is whether it's a reasonable swap when it comes to the frame. Do things fit reasonably? I'm seeing a 1.5" difference in wheelbase (the new trucks are longer), that doesn't seem like a big problem. I suspect modern suspension geometry is better, rear discs rather than drums, etc which is why I'm considering it.

Thanks for any help. If I don't, I certainly need to find a smaller carb... probably 500ish. That would help with mileage, but not cruising speed.

[andrewmp6]

People have done it but its a monster job you have to fab almost everything.I would swap in a ls engine and 4l60e trans in your truck the way it is.

[68c10owner]

Best bet is to do a drivetrain swap over a complete chassis swap. But remember there are frame numbers that match your vin tag. You get a savvy CHP or DOT inspector and they notice a later model chassis you are opening up a can o worms.

[slotard]

I was figuring the modern frame and suspension was probably better, I know I'd prefer a newer rear end with discs. I'll have to figure out whether, with overdrive, I'll want a 3.73 rather than 4.10...

If I do a swap it'll be a 4L80E rather than the 60, it's a 3/4 ton and sometimes I like to use it like one.

[68c10owner]

You should be able to retro fit the later rearend. Some of the suspension may fit as well bit that chassis are different and it will be a lot of work to make the early body fit.

[slotard]

What makes it so hard to swap to the modern frame? Is the width significantly different, or is it something else?

And yeah, whether I use the frame or not I'm going to look for a crashed truck so I don't need to buy as many little things.

[v30crewcab]

better do some checking. I've always heard cali goes by the frame number not the cab. i've seen a bunch of builds using 75 and older frames for that fact.

[wilkin250r]

Not only that, but because smog restrictions are SUCH a big deal in California, they have a whole set of regulations involving engine swaps, which I imagine this would fall under, and using a 99+ engine and chassis very well might require smog inspection.

I don't know all the details, but I'm only a few miles from California, and get plenty of exposure. You might get lucky, 1975 and older might be different, but I know I had a friend looking at swapping an 2002 LS engine into an 87 truck, and California was going to require him to meet 2002 emissions regulations because of the engine, which were obviously much more stringent than the 1987 emissions regulations.

[slotard]

I've never heard of someone's frame VIN being checked, and I'm not sure where it even is. I have friends who have made their own frames and none of them have had any problems. Where would I even find the VIN on my current frame? AFAIK what gets checked is typically on the dash, occasionally the door too.

Yes, officially I'd need to keep all the smog equipment from the modern truck. However, there's never any sort of inspection required on it. 76+ gets smogged every other year, anything older gets nothing. I have plenty of friends who have done engine swaps in old vehicles (way more than frame swaps). Exactly one had problems, and that's because it was backfiring and generally running poorly, to the point that it was obnoxious. I've heard it's also more common in street racing areas but I don't do that.

[KQQL IT]

All the equipment is supposed to be there, no matter the year.
Just no inspection required prior to 75,
Looked into it even an Erod engine requires a lockup converter to be technically legal.

All that being said I've never been looked at with my 73

[slotard]

http://ls1tech.com/forums/conversion...chevy-c10.html doing some looking I found that.

I believe there's already some equipment missing on my truck (bought it that way), I'm not too concerned as long as I'm not a dick to cops.

[slotard]

For now lets say doing the paperwork I need to isnt an issue... what makes this a difficult setup?

Whether I do frame swap or just engine swap I'm supposed to retain the emissions equipment on the new engine, so that's the same either way.

[andrewmp6]

And i wouldn't bother with a newer rear end you gotta weld on new spring perches and shock mounts.And that is even if both are close in widths and they probably are not.You can get a rear disc kit for any drum axle out there.And gearing you can always change them if you can't do it a shop can for you.

[slotard]

For me, it's easier to weld on new spring perches and shock mounts on a rear end that already has the gears and locker that I want than it is to put the gears and locker that I want in mine. It's also hard to find a good disc brake setup for 14FF that has parking brake.