Hey guys. Long story short I have a 53 4400 cab and chassis. It has a running 235 and sm420 trans with a modern 97 chevy 4.56 rear axle. The 235 runs but needs a rebuild. Here's my plans. I plan on putting my 5th wheel on it. No bed... well as of yet. And a heavy duty tow package for pulling heavy duty trailers. I'm looking for engine and transmission options. I have a 2003 chassis with a ls1 and 4l80e trans. I was going to cab swap but the steering won't work and leaf springs won't work. Ide have to cut the front of the frame off then I loose my leaf spring mounts. Anyways, what engines and transmissions can I swap out the 235/sm420 with? Ideally ide like to swap my ls1 and 4l80e into it. 3 times the hp. 3 times the torque. But the frames are way different. Width and all is way narrower in the 53. Plus the 53 has a WAY heavier duty frame. So what's my options?? Can I swap my v8 into it? What do I do about the engine clearances? Like steering components and such?
