I did EFI with dual tanks on my ‘78. I used stock replacement NON-EFI tanks, and two Holley drop-in EFI modules. I used a Harnessworx dual tank/relay harness and high pressure Pollak switching valve. Re-used the stock steel fuel line on the frame, and EFI rated hose and clamps on the tanks/valves. The harness has a single fuel pump power wire which can be triggered by any EFI kit (I used a Terminator X), and it switches power from side to side also as needed. It’s a pretty slick setup, very easy to put together.
You can see my tank setup in this thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=806842
As a whole, these trucks are extremely easy to perform LS swaps on. 99-02 truck 5.3L’s being the easiest. I would recommend the Dirty Dingo sliders. 2010+ Camaro exhaust manifolds fit very well. A 99-02 Truck throttle cable works with very little modification. 99-02 truck upper and lower radiator hoses fit great. Oreilly’s has a stock replacement radiator that now has the option to thread on a barb for the steam port. You can use 99-02 power steering/hoses with CPP adapters to your steering box, or they will thread right in if you have a later box - minor bends necessary on some hoses, but they do work. LS alternator can be used with a simple adapter harness. It’s also easy to do dual oil pressure and coolant temp sensors to keep both your EFI system happy and stock gauges functional. If you have no body lift, the LS mechanical fan fits very well in the stock shroud.