I just purchaced the intake on ebay it came with the injectors and fuel rail no TB ill be getting a holley 90mm cable TB. got Intake for 120. only 1500 miles he switch to a maggie. And i have been watching for 8.1 marines also.

 

You can use the injectors that came with it (although I don't think they are enough for a 408) if you change the plugs for the wiring and I have seen where you can use a Corvette fuel filter/regulator on the end of the TBSS fuel rail to connect to the return fuel system since it has 2 lines in and 1 out. Hard to find any good information about that though. You might search for something like Corvette filter return fuel system swap. As expected some tuning will be needed for the injectors either way and the tuning will be a little different with the corvette filter/regulator since it is atmospherically referenced instead of vacuum.

Another solution would be to buy after market fuel rails and a regulator but that will be much more expensive.