I have a 1997 LS1 that I'm swapping a NNBS 5.3/4.8 intake onto, and I've seen some different opinions on what electrical adapter to use for the throttle body control. I think most everything else will be pretty easy to cover, Katech has a MAP sensor adapter that should work fine, but I still need to figure out the TB control and injector electrical adapters as well. If anyone has had good experience with any particular brand or item, I'm looking for suggestions.

PS-I don't have a stock LS1 intake, the engine came from a burned car, and it's going into a 2000 Corvette

 

Contact HPI (High Performance Injectors) for your throttle body and fuel injector wiring issues. They can work with you and get you what you need.
They fabricate standalone harnesses, pigtails, etc.

Michigan Motorsports and ICT handle a lot of electrical pigtails as well