I was thinking of an Explorer member I know with a 12 second SOHC 4.0 now. He's got 15-18psi and the 5R55E is miraculously still surviving. He has a restrictive exhaust, and an Eaton of I think 122 CI size, close to 2 liters. He's just about at the limit of his combination, aiming for a touch of NO2(I think the trans is going to let go soon).
Using a SBF trans would be best, the 4R70W is strong enough for an auto. Which trans are those Ford Barra motors made for, the bell housing pattern?
92 Mark VII LSC SE - soon OBDII and 4R70, GTC kit and 347, custom paint.
98 Explorer Limited project to add 4WD, XP8 parts, KB blower, paint, 337.
99 Limited mail vehicle, SOHC 4WD, later 306/4R70W swap. 1998 Mountaineer spare. 72 Ranchero 351 Clevor project.