You're talking a whole lot more work to put that 5.3 in your truck. It will end up costing you alot more than you think in the long run unless you try to cut some corners (not a good idea). And from what I read it looks like you're shopping for someone's used motor.
If your other option is to build a brand new 383 then my decision would be made. I mean, how many times do you want to start over?
I'd build the new 383, stick it in the truck. When money shows up down the road, add the fuel injection to it.
Think of it like this............
383 = Brand new engine with WAY more pull in the low range.
5.3 = Used engine ALOT more work.
Like I said, my decision would be made
