E7s are too small for a 351, but the 351s were only used in trucks by then and torque is the name of the game, not power. It might be totally out of breath by 4500rpm, but useable torque will come on probably around 1200 rpm.
and yes, I believe they did come with E7TE heads. The T is for truck.
Acutally the stupid things run out of breath around 3000 rpm and torque comes off idle. Im not correcting you, Im just telling everyone how gay these truck 351 motors are..
My 90' Bronco that just lunched a piston and rod in its 351 had em. They really hold the 351's back. I just pulled my engine and tore it completely down for inspection a couple of weeks ago. The heads are casting E7TE-PA.
My Bronco's about to get a Pro Topline 200cc or 215cc headed 408 stroker. Should give me good experience for my future Fox Body street/strip terror.