Fuel pressure vs injector size...need some common sense help

[kilohertz]

In my quest to tune my engine, (239 cu in flathead Ford) I am trying to decide whether to increase the fuel pressure to 20 PSI and use the 2.8L injectors which I have, or install 4.3L injectors and run at 13 PSI, which I would need to find. I need about 110HP for the flathead, and can JUST get it with 33pph, the 45pph of the 4.3 would give me 118HP at 13 psi. I am kind of leaning toward the 4.3 injectors, and hopefully will be able to dial them back at idle and still have enough BPW at WOT. THE BSFC of the flathead is about .65. I bought a stock TBI pump, 12-26 psi but am not sure what it really would develop in the real world. The 10-14psi pump I have now won't go above 10 psi, even dead headed. I can buy the 7.4L TBI pump locally, 39-54 PSI, but if I don't have to, I won't.

Just need a little guidance from someone who has been down the tuning road before, to confirm my thoughts before spending $$$.

Cheers and thanks!

PS 1227747 ECM and 2.8L throttle body

[In-Tech]

Hiya,
If you are talking about the in tank pump, replace with '96 vortec pump, drop in replacement capable of more than 60 psi(the regulator controls this anyway regardless of pump, unless pump can't make pressure).