I am currently in deep in this very situation. ‘70 C10
Things to consider:
Computer and wiring: I’m not here yet but will be shortly. I will be using information from this website to help me. It is a bit overwhelming for a rookie/newbie. I still nervous, but as my fix anything, ole boy, hit it, old friend of Dad neighbour used to say, “A man built it. We can fix it ( or in this case hot rod it)!😉http://lt1swap.com/
Fuel system: you will need to figure out the fuel pressure system to the rails on the intake. Return? Returnless? Fuel filter setup/regulator? Stock tank? After market? Can get pricey.
Engine mounting. This is not a bolt in with stock items. There are many kits available to mount the ls into just about anything. I used Dirty Dingo, so far so good during mock-up.
Emissions? What are your state’s laws? Does your truck have emission equipment? Does the state require you to keep it? Look into it. It might cause you grief if you don’t. Not to mention money. Up here, smooth sailing for me with just about anything.
Active fuel management/deactivation came in around 2003/2004 (don’t quote me), and will be a factor in which truck donor you get.
Front belt setups: make sure your gathered parts play nicely and line up on the front of the engine. I’m sticking with the awful looking truck setup. Cheap and it looks ok with some cleanup and paint.
Trans mount should be ok to use.
A/C? - the stock 5.3 truck compressor JUST clears the frame, when bare and nothing hooked up. I suspect I will have to notch the frame rail slightly if I use a stocker.
Radiator: trans cooler included? The fittings will be different possibly and routing. I’m investigating this.
Steering: the modern pump might use a different fitting. I am researching this right now, too.
Exhaust: the stock truck 5.3 will not clear the frame rail. I heard people say, “NOTCH THE FRAME,” but my mock-up experience showed a ridiculous amount of notching, to the point of frame integrity being lost. Get new manifolds.
Trans control: will the tranny talk with your gauges? Look into this. I am too.
Wrecker truck: agreed. I got my truck for $900. 215,000km/ 130,000mi. Engine, trans, computer, etc minus the alternator and steering pump. THe front seats had been sold, but I suspect I might make back $200 on the axles, tires, etc. Plus, now I have extra door handles for when my ‘04 Duramax latches break. It happens. -40°...stuff gets brittle. I haven’t driven it in over a week!
4wd vs 2wd? I bought a 4wd truck, but had the transmission overhauled because of 3/4 being burned out. The shop switched it from 4wd to 2wd for me. Since computer will be reflashed, I wasn’t concerned about it.
It is a pile of extra work in my mind. Time will tell if I ever do it again. I have to drive it to see.
I’m still plugging away at it. 8 months later, still here...Mind you, I am doing a frame off build.
The snowball effect.