Red Headed Stepchild-75 Swinger LSX Swap
I've never heard bad about the Holley intake. My preference leans to the FAST intake, though. Try and find an LS6 intake for the inexpensive alternative. Definitely get an adjustable fuel pressure regulator if you're going to run the big injectors. Remember the Ford Motorsports injectors will work, too. I look forward to seeing your progress.
The Holley and FI tech Manifolds are relatively new. They are essentially the same design as the ebay manifolds but seem to have a little bit better craftsmanship. Like they literally took the failed design of symbol performance(because in the hotrods test the symbol picked up 57 hp over the LS6 manifold) and threw a little better materials and welds and then threw their name on it.
20 LS1 Intake Manifolds: Tested!
I will be using an adjustable FPR for sure and have had great success with the Aeromotive style ones in past builds.
And if you look at the link above, the difference between the truck manifold and the ls6 manifold are below, on the same engine, same injectors, same throttle body.
Truck - 549 hp @ 6900, 481 tq at 5000
LS6 - 557hp @ 7000 483tq @ 5000
I already have the stock truck manifold with my motor, I cant justify 200-500 for an LS6 manifold, just to pick up 6 hp and 2 tq. If I were going that route id go with something like a speed master for around 200, which made 561hp @ 7000 and nearly identical torque(although part of that could have been due to the 102MM TB).
But if I do make a change on the intake manifold it wont be until after I have the motor in place and figure out how high an intake I can run on it without hood clearance issues. plus the biggest point of this swap was to prove how cheap and relatively easy it was to do the swap if you were smart enough to do the research and shop around. So maybe just swap in the stock motor with the turbo and upgraded fuel system upgrades and see what she does. Then wait and save enough money for a nice intake and tb setup later on down the road and do a side by side comparison.