I was talking to a radiator shop owner today and we were discussing nailheads and I thought I knew the torque ratings of 401 and 425 engines, and then I confused myself. Okay, a 401 has 445 and a 425 has 465 (I think), but what about a 425 with two fours? And then there is the Q-jet in 1966… help!
425 was rated at 465 ft lb with either the Q-jet or 2x4. I think the 425 was rated at 445 with the AFB, same as the 401. But we know "listed" numbers were all over the place in some cases over the years. Just go with "gobs" and you won't be wrong.
the 1966 skylark GS had rare engine options the 401 with a Q-jet and one with higher compression made 340 HP. Walt would know more about this. the 425 in the bigger Buicks with 2x4 made 360 HP over the single 4 with 340 HP but both had the same torque rating with 465.
I think the super rare 66 11 to 1 comp 401 that had a 332hp. rating was rated at 450 torque or at least on some magazine articles..
The 66 GS 401 with Q-jet 10.25:1 CR was rated at 340 hp by Buick..... With the 11:1 CR it was rated at 332 hp by the NHRA. Go figure! The Q-jet and different cam (the 2x4 cam with 109* lobe separation) did help at higher rpm. Higher compression definitely helps too. Obviously Buick's Marketing dept determines hp differently than the NHRA does!
