454 to inline 6 swap in a crew cab c20

[dragn91]

I bought a 80 Crew cab 454 truck a couple months back and it's a lot of fun but the gas mileage does suck I didn't think I'd drive it as much as I do but I really like the truck. I found a truck cheap down the road that's a 292 inline 6 and it has a really nice bed mine is junk. Would I be crazy to drop the 292 down in my crew cab or would it be a complete turd? I'd like to keep the 400 turbo until I can find everything to convert it to a manual column shift or take the 4spd out of the donor truck as well. There both c20 trucks I figure an extra set of doors and couple feet of cab can't weigh that much right lol. And this should pretty much be a bolt in job right as long as I keep the trans where it's at? Or would I need to shorten or lengthen it?