Well damn. I already bought a t4 flange and I expected to have to make the t4 to 2.5". W/e, I guess I will anyway.

Do I still need that fuel pressure regulator if I do that drill and tap on the fuel pump and run the boost line to it?

69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.