I have a 1985 D-150 with 318/727, thinking about maybe swapping my 400/727 into it. The 400 is out of a '75 Cordoba, I already have the BB truck brackets and manifolds, what other issues am I looking at. I was told that the brake booster may have to be changed for a big block, but some said that only for a 440, not a 400. Am I going to have any issues with power steering? Such as the car brackets/hoses/pump not working with the '85 truck box, etc. I know that I will have to lengthen the ignition wiring harness, which is no big deal. I'm just trying to figure out what I will need. So to summarize, I have a 400/727 out of a 75 Cordoba, BB motor mount brackets/kickdown from a truck 440. Not sure about the radiator, will a small block truck radiator work with the 75 B-body 400 water pump housing orientation? Or will I need to swap radiators or water pump housings?

You will have to compare the lower outlets. A radiator shop can fix you up. Power steering could be a problem. Some configurations work some don't. Was the Cordoba an a/c car? Is the truck an a/c truck? Booster should clear a low deck but again it could be close depending on the booster. Kick down linkage may not clear. Its a do able project just you need to get into it to determine what mods are needed.

I built a 360 and auto to go in a 1985 w-150 that was a 6 4 speed. That 360 with the right cam, headers, carb, intake, and converter was a rocket. Plus it was an easy swap.

You need a truck oil pan/pickup tube/dipstick. Only way to know if the hose orientation will work is see what side the 400 is at. You'll also need truck ps brakes unless yours sits high enough to clear. Only 440 needs a booster swap. I probably have all the other parts you'll need. I have a 400 from a Ramcharger that's heading to scrap. Planned to pull truck related parts and sell so if you need them pm me. Pass side lower hose outlet is what you'll need. I used my small black rad for my 400 swap and it kept it cool. I also installed an electric fan to ditch the mechanical one.

I have a dead 440 from a 78 3/4 ton 2 wheel drive with motor mount brackets, kickdown, truck oil pan/pickup etc, so should be good there. I have a few radiators laying around, so should be able to make something work there as well. I thought low deck BB would work with the large diameter booster, so should be ok there as well. I'm hoping that between the small block ps brackets in the truck now, the 78 440 ps brackets and the 76 400 ps brackets, I should be able to make something work. The sb in the truck now is AC, as is the 400, Will probably eliminate the AC, as the truck is a small rotary compressor and the big blocks are the older style of course.

Unless dealer add on ac

I don't know if it was said already but you should take the front spring out of your 78, the 400/440's are a lot heavier than the small block and the stronger springs make for a much better ride. I install a 400 in an 81 3/4 ton, works great for towing my trailer

No need to swap springs. I never did and other members even stayed with what was in it. mine road fine