67 twin turbo dart

That is a huge discrepancy if your wideband is correct. Something is up. Make sure fuel pressure is rock solid first. Sounds to me like your regulator isn’t rising with boost.
Just went out in the garage and idle psi is 32, and when revving it psi jumps to 40, its good up to 100psi, fuel pump Info 400LPH (100 gph) at 40 PSI, 340LPH (90 gph) at 73 PSI, and 270LPH (71 gph) at 120 PSI.