Yup, T/As and GTOs. 335 HP, 455"HO" (High Output). ALL T/As in '71 were equipped with 455HO. A handful were in T-37s. Good head for a large cubed engine. HUGE combustion chambers (around 110 CCs). Better left to restoration guys these days. The Edelbrock head is "better" right out of the box, and it's by no means, "ready". Once the E-head is "ready", FAR superior to ANY factory head short of Ram Air V.
I've recently seen a very nice pair of the 197s go for $1,500. They were in excellent condition and the date code was what the buyer was looking for.
Jim
