Frame strength questions 10 vs 20 vs 30

[notchbackgta]

I recently bought a 69 C10 Suburban that I want to make into a 4x4, but it has a coil spring rear. I just missed out on an 82 K30 that I was going to use for the frame and suspension under the Burb. Finding another one in the same price range, was only going to be $1,400 running and everything, is going to be difficult with low rust in this area.

I do have a frame from the same gen 67-72 GMC c15 with the leaf spring rear that I was going to put under my 69 C10 pickup since the coil truck frame has a few problem spots now. I got it with the the really nice bed that I needed to complete my truck

With what ever frame I wound up using under the Burb, I planned on boxing anyway. I plan on putting a diesel engine in the Burb in the long run and using it as an expedition rig(ish), so it will probably have lots of other stuff that will make it pretty heavy.
My question is, should I hold out for something better than the C10 frame, or will boxing that be strong enough?
Thanks

[andrewmp6]

What diesel are we talking tho?If your gonna run a 12 valve cummins i would wait for a k30 frame to use.If your going to use something lighter like a 4bt the 1/2 ton frame would be good.

[obijuan]

A properly boxed frame will be much better than a k30 frame.

[1972K20]

What about a properly boxed K30 frame?

[obijuan]

That would be obviously better than a boxed half ton frame.

[ryanroo]

my first concern is frame swapping. if you are wanting a heavier strength frame you can use a k20 burb or truck frame from the 69-72 trucks. there are a few mounting differences in the burb and truck frames, but the contours are correct and everything fits. a non-like year frame swap is asking for headaches. its hard to get it right and really easy to cheese the crap out of it.

if you are building an expedition rig a cage is in your future, or should be. if you saw my k20 build, i would say box the 1/2 ton leaf spring frame like that and build a righteous cage that is well tied in. that will provide you with a very rigid and appropriately strong chassis for your rig, no matter the engine chosen.

the dimension added by the cage will make the frame way better than any K30 frame and you dont have to worry about aligning the frame and body, accommodating the difference in WB and the always present threat of frame swap hackery.

[notchbackgta]

Thanks for the replies.
I said expedition(ish), I don't want to go so far as putting in a cage as I don't want to see it, nor have to build anything around it. I plan on going off road maybe a few times a year and not mudding or rock crawling, but I plan on using it to live-in for potentially weeks at a time, so I may have a lot of "extra's" built in. I have a nice inverter and plan on a freezer, roof rack, hitch setup at least a front winch and some fabricated steel bumpers since I don't like the look of the stock ones with holes cut etc for tow points. I'll have 2 or more batteries to run stuff while I am camping. I am also planning on a 6bt since I really haven't seen any 4bt's for sale in any of my searches. I see Dodge 2500's all the time in a price range I am comfortable with all the time and now that spring is here, more and more 4x4's that are getting cheaper. As time goes by I will probably go offroad more and more, I have to get out of Communist New Jersey as soon as I possibly can, I just wish I didn't have such a well paying job and family/friends here, it would make the decision to leave a lot easier and do it right away.
I would have went with a K20 suburban to begin with, but since the vehicles of this era have enough rust problems rust was my first concern, and I was only able to find a C10 with an acceptable amount of rust that I could, 1; afford and 2; was withing reason travelling distance.
I don't see how the frame swap from the later gen is all that big a deal. Looks like most of the mounts for the burb are on top of the frame, without any protruding side mounts, like the cab does, even at that I can cut and weld some box steel to make what I need. And the width of the next gen frame is pretty close to the same width, unless I am completely off. I am going by the knowledge that the front 2WD crossmembers are basically a direct swap.

I guess I will keep my eye out for a K30 frame since I am not in an extreme hurry to get this a 4WD, though I got stuck in my friends yard over the weekend just trying to turn around, one wheel drive REALLY sucks. I kind of need to have something worked out for next winter though as I need to be able to get out in all weather conditions as I am an "essential" personnel now at the utility company I work for.

[notchbackgta]

Originally Posted by ryanroo

the dimension added by the cage will make the frame way better than any K30 frame and you dont have to worry about aligning the frame and body, accommodating the difference in WB and the always present threat of frame swap hackery.

Another thing that makes me think the next gen frame won't be all that big a deal is the K30 WB was only about 2.5-3" different than my WB as is now with the trailing arms. I could have fudged that with some zero rate add a leaf's on the rear springs

[andrewmp6]

Around me a 4bt and 12 valve sell for about the same price i rather have the bigger one.The 4bt shake and rattle worse then a 12 valve at idle.But the 4bt weighs about 700 lbs vs the 1100lbs for the 12 valve.Either swap making sure the trans and t case can handle the power is key.

[1968vetL-71]

I would be careful on boxing the frame. Frames are meant to flex to a point and move around. If you box the frame that makes it very rigid and when Its time too move around a bit or twist a bit... something else is gonna take the abuse.
There have been hundreds and hundreds of cummins swaps in 1/2, 3/4 and 1 ton pickups, suburbans and even blazers that did nothing to the frames.

I know its a preference, and a "well I heard" thing, but there are plenty of boards and build threads out there to get educated enough on.

Good luck tho!

[notchbackgta]

Originally Posted by andrewmp6

Around me a 4bt and 12 valve sell for about the same price i rather have the bigger one.The 4bt shake and rattle worse then a 12 valve at idle.But the 4bt weighs about 700 lbs vs the 1100lbs for the 12 valve.Either swap making sure the trans and t case can handle the power is key.

NV4500 and NP205 are the plan...

Originally Posted by 1968vetL-71

I would be careful on boxing the frame. Frames are meant to flex to a point and move around. If you box the frame that makes it very rigid and when Its time too move around a bit or twist a bit... something else is gonna take the abuse.
There have been hundreds and hundreds of cummins swaps in 1/2, 3/4 and 1 ton pickups, suburbans and even blazers that did nothing to the frames.

I know its a preference, and a "well I heard" thing, but there are plenty of boards and build threads out there to get educated enough on.

Good luck tho!

I know, inherently, that the frames flex but I didn't think that was an intended design, nor did I think it was desirable. I can't imagine the need to let the frame flex and cause the doors to not open/close to be an intended design. I watched a video of a Dodge and Ford truck (stock 3/4 ton I think) on one ramp to induce flex and the doors on the Ford wouldn't open or close, something like that.

[Mr. 250r]

Originally Posted by andrewmp6

Around me a 4bt and 12 valve sell for about the same price i rather have the bigger one.The 4bt shake and rattle worse then a 12 valve at idle.But the 4bt weighs about 700 lbs vs the 1100lbs for the 12 valve.Either swap making sure the trans and t case can handle the power is key.

I can attest to the 4bt rattle we install 4bt and 6bt isb motors at work and the 6bt's are solid mounted to the frame the 4bt get rubber motor mounts. These are all installed on tube frames for industrial drills that we build.

[notchbackgta]

I went and got an 88 GMC K30 CCLB, mostly for the axles and transfer case, but I am thinking about using the frame, if it doesn't sell after I get the cab and bed off the frame