Real world what fits / what hits

[ChevyKev]

This is great. I was able to talk it out before spending money on the wrong things.

Originally I was limiting it to 35's because of the 10 bolt diffs, 700R4, and NP208. I got looking at all the tires and starting thinking bigger was better, but not the case for this build. I was thinking locked/spooled rear and locked front. Really thinking about ARB air lockers because this will be driven on the street quite a bit. It's stock with 3.07 gears, but will gear lower depending upon final tire size. Like Kevin said, 3.73 would probably work, but 4.10 would be better. I like low gears, my old F-350 used to be 4.30 behind a V10 with stock tires. Now I'm 90% certain to go with 6" lift and 35" tires on the 1/2 ton.

Sounds like a good plan! The only caution I have for you on the ARB's is that most people I know who run these up here eventually have air line problems. The cold just effects them. Not that they are completely unreliable or bad, but be aware. I also would suggest the heavier air line - you could get more info from Ronster - he is a vender for these and just installed a front ARB with the heavier line.

I am also looking at a more serious build for off-road use. I now have a 1975 K20 with a 327/TH350/NP203. There is a 1985 C20 I want to buy. I'll take the body and transplant the 454/TH400 onto the 1976 4x4 frame. May have to stay with the NP203 for now, but will probably replace with a NP205. Thinking 39" tires for on/off road and maybe some 45" tractor tires for serous offroading. This truck will have 10" of lift and cut fenders. I'll run the D44 front until it dies, then upgrade to D60. The 14 bolt FF rear should be fine.

I know where a 205 that bolts to a 350 is...

If sticking with the 39's, don't go 10 inches of lift. Go 8 and cut - or 6 and truggy (narrow front and rear fenders) this keeps your center of gravity lower.

If by "serious offroading" you mean simply mud bogging through flats, 10 inches of lift and 45 tractor tires would work great!

However - take that same vehicle up 55 Mile trail or Rainbow mountain area and you'll be regretting your high center of gravity - any off-camber situation would be a serious pucker factor with that much lift and thinner tractor tires and flopping would be inevitable.

for example