barn find 67 c-10

[CC69Rat]

Most of the 4/6 drops with 20's run a 295/40/20 So in comparison (for the rear)

295/25.4 = 11.61in wide
275/25.4 = 10.82in wide

Keep in mind, with a 15" wheel vs. 20" wheel you might have a little more sidewall 'puff' so the overall section width of the tire might be slightly larger than what of a truck with 20's.

In the rear, you are to a nice advantage in that a 67 rear end housing is 1.5" narrower than a late 69-72 housing. (so you can run less backspacing and make your wheels look wider)

Ex. 4/6 drop and narrow housing.

I would run a 20x10 with 5" BS and 295/45/20 (I just like a little more sidewall)

The same drop with a late housing, 20x10 with 5.5" BS This just offsets the extra width of the axle. I would think (just my opinion) on a 15x10, 5" BS would sit you nicely. Others may chime in and that's cool. Just my thoughts on it.

Up front, you might be a little tight with a 15x8. What I mean is the lower A arm specifically. I wouldnt sit it too far back under the truck just for turning and overall suspension clearance. This is not so much of an issue running 20's or the larger wheels just due to the diameter and of course more clearance in this area.

likewise, most run a 20x8.5 up front, with 5.25" BS. 255/40/20

255/25.4 = 10.03" wide either scenario but remember the sidewall 'puff' .. not a bad thing, just something to keep in mind. If it were me, I'd do the 15x8 with 4.75" BS. My thinking is 8" vs 8.5" in my previous example. You'd knock off the extra wheel width from the backside and help with the clearance issues but that tire is going to be out there too. .. humm. 5" BS on all 4 corners?

Not responsible if it doesn't fit.. I'm just saying, that's my logic on it. Hope it helps. Comparing an early housing and discs up front as the baseline. Non modular, or big brakes.