[cjperformance]

Originally Posted by Joshinator99

Tuning the FSCM can help to some extent but don’t expect any miracles. You could probably add a JMS voltage booster to the LT1 in-tank pump to get more out of that. And you can obviously continue to use that when you change to the LT4 in-tank pump.

The LT4 in-tank pump is pretty cheap and is needed first. You can definitely do that without doing the rest of the fuel system at this point.

The LT4 HPFP will be the next weak link. You should replace the high pressure pipes every time you interrupt them (two pipes, maybe $75 for both, see attached). I would also recommend the LPE high flow check valve to replace the very restrictive LT1 version. You’ll then do the LT4 injectors when you do the LT4 fuel pump because the operating pressure is higher (2900 LT4 vs 2175 LT1). Adding a cam at some point will let you get 32-40% more out of the HPFP.

Awesome info! Thanks!