It was a good thing I did this, a couple injectors wouldn't open at all until soaked. I had them all consistently working by the end. I would connect a neoprene rubber vacuum plug with a small hole poked in it for the straw on some carb cleaner, pressurize with the cleaner, then click the button until I had good, clear flow and a decent spray pattern. Nothing scientific, just went until each one looked like the last.
The next step, I installed up the Holley Fuel rails PN # 534-210. They were one of the more economical, high quality options with o-ring fittings (vs pipe threads) and a complete set of fittings.
One of the tougher parts was deciding where to put the filter pressure regulator unit. I was considering placing it above the subframe like Pstl_Pete's LS3 hatch build, but I couldn't help but wonder what will happen if I get traction and break one of the still stock axles, I would rather just replace a hose than the whole unit, and the rear subframe and axles will be a later project.
I ran the line just beneath the brake line with some cushion clamps and covered the line in fire sleeve to try to protect the rail from the -6 stainless steel line.
I bought this Koul Tools -6 assembly tool towards the end of making the -6 lines after struggling to put a few fittings on, I always have struggled with the smaller sizes. I wish I would have bought it sooner, it made it so much easier. It's well worth the money if you put very many fittings together, stabbing your fingers with little stainless wires gets old after a while.
I used one of the Summit -6 to 1/8 fuel pressure gauge fittings with a little fuel pressure gauge I had sitting in my tool box so that I could keep an eye on fuel pressure.
