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I would say that this may be the answer to this question, wheels and ride height look the same. Quite a few C/K cab 3500s with that extra grille valance between it and the bumper. May require a different steering column / steering shaft to the gearbox. I'm also told the P-series steering gear box is mounted differently.
 

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I used a P steering box on my '37 GMC in a conventional location, P just mounts differently.

Ed in CO
Mounts differently, as in just positioned differently on the P, with the same mount holes and spacing? Parts stores show a different part number, but that could be as simple as a difference in steering gear ratio.
 

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I am not sure if I have a P30 frame or not, but my 78 F-250 is sitting on a 1997 Grummins box truck frame that the P-pump 4bt was installed in.
I liked the idea as my 78 frame has seen to many New England winter and was rusted alot. A few things I liked about the 97 frame is, it has the same spring perch centers as my 78 Dana 60 did, 32" on center ( yes the 78 60 is actually 31.5", close enough. ) and even a Chevy 60 could bolt up.
Its 8"s tall 5/16'' thick, open C channel so it was easy to clean and paint. NO pockets for water to settle in so it wont rot like most NE trucks do.

I used the OEM steering box and other than drilling out the stock Dana 60 steering arm to except the larger taper of the TRE that bolted right up. I used the stock motor mounts for the 4bt and the cross member under the oil pan, I had to move the mounts back on the frame and drilled 4 new holes each side to bolt them back up.

The bad, well kinda. It made the truck look like it had a 6" body lift in the front as you can see right under the grill. I cut the Ford grill to clear the steering box and after installing it I now see I did not need to chop such a large hole, I will plug it.
Things like body mounts needed to be fab up and a rear crossmemeber for the body needed to be made, but I am happy with my choice.

The project got shelved as I started a welding business and that is taking time away from this truck.
 

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I am not sure if I have a P30 frame or not, but my 78 F-250 is sitting on a 1997 Grummins box truck frame that the P-pump 4bt was installed in.
I liked the idea as my 78 frame has seen to many New England winter and was rusted alot. A few things I liked about the 97 frame is, it has the same spring perch centers as my 78 Dana 60 did, 32" on center ( yes the 78 60 is actually 31.5", close enough. ) and even a Chevy 60 could bolt up.
Its 8"s tall 5/16'' thick, open C channel so it was easy to clean and paint. NO pockets for water to settle in so it wont rot like most NE trucks do.

I used the OEM steering box and other than drilling out the stock Dana 60 steering arm to except the larger taper of the TRE that bolted right up. I used the stock motor mounts for the 4bt and the cross member under the oil pan, I had to move the mounts back on the frame and drilled 4 new holes each side to bolt them back up.

The bad, well kinda. It made the truck look like it had a 6" body lift in the front as you can see right under the grill. I cut the Ford grill to clear the steering box and after installing it I now see I did not need to chop such a large hole, I will plug it.
Things like body mounts needed to be fab up and a rear crossmemeber for the body needed to be made, but I am happy with my choice.
I believe the main difference between the P30 and the P20 is the P20 uses 16-inch wheels, the P30 uses the larger 19.5-inch. Seems like the 20 is a 1-ton, where the 30 is 1.5 - 2 ton. I also believe the 454 was only available on the P20, not the P30. I currently reside in a P30 RV with the 454 and 19.5-inch wheels. I also own one with the 16-inch wheels and the 6.2L diesel, which leads me to believe it is a P20, not a P30. However, some other info indicates the one I currently use is a P32 chassis, not the P30, though I'm pretty sure this is simply a softer suspension and independent up front rather an I-beam axle.

As for Grumman, I believe they used both Ford and GM chassis, which might explain why your spring perch area fit your Dana perfectly. GM used Rockwell, exclusively AFAIK. Though Grumman has largely given over to Ford chassis as of late, a '97 could be either/or. One thing I've noticed with a lot of late-model 3500HD GM pickups is they usually have the same 19.5-inch wheels the P30 does, and they, too, have the six-inch body-lift look you describe. However, GM corrected this with grille-extension valances on these. This all makes me think the 3500HDs actually sit on a P30 frame.

I'm not sure if it's a be-all-end-all, but I've noticed subtle differences on the stock steel wheels for these trucks in regard to Ford vs GM, be it the shape of the hand holes, or even the number (I've noticed some have four, some have five. I believe GM usually had five hand holes, Ford usually four, though I would think eight-lug and ten-lug pattern uniformity allows use from one to the other. Pretty each manufacturer had their own design or suppliers though in regard to styling. The only way to know for sure is to see if there is a tag on the frame. Most manufacturers put some type of tag on the frame to indicate they manufactured it.

In lieu of the frame tag, components such as the steering box would tell the tale, I'm sure. Sounds like that's about the only original piece from the donor frame you used.
 

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I used the original springs, dropped a leaf in the front, the spring pack in the rear dropped two out of that set, the steering box, fuel tank, rear sway bar, frame, exhaust/down pipe and of course the P-pumped motor with after cooler, all the turbo pipe/hose's and rad.
Mine had 19.5" tires and rims but a large 6 lug bolt pattern, traded a tow for the tires, rims I got back.
I scrapped the body ( Alu ) and sold the I beam front, rear Dana 70 HD and rims for good money.

For a running driving truck I paid 600.00 dollars for I think I am ahead of the game, oh sold the SAE #2 adapter, bell housing and flywheel, Those are the only parts I wish I kept lol.
 

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I believe the main difference between the P30 and the P20 is the P20 uses 16-inch wheels, the P30 uses the larger 19.5-inch. Seems like the 20 is a 1-ton, where the 30 is 1.5 - 2 ton. I also believe the 454 was only available on the P20, not the P30.
I meant to say here that I believe the 454 was only available on the P30, not the P20. "Beavis, you dumb-ass..."
 

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Discussion Starter #30
I ended up dropping the 4bt into a Chevy 2500 then I dropped it in a Ford F350 Super duty. I still beat on it daily, it's hard to believe it's been close to 5 years now.
 
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