6 The guys at Proform sent us these handy head stands (part no. 66481) to use while we checked out our new Trick Flow Specialties heads. The combustion chambers are 113 cc, the same as the factory heads, so the motor’s compression will stay the same. They come fully equipped with stainless steel valves (2.190 int./1.880 exh.), dual valvesprings, 10-degree locks and retainers, high-temp viton valvestem seals, new ARP rocker studs, and adjustable pushrod guideplates. We pulled one of the springs and checked the installed height, and while taller than what the old heads were set at, the seat pressure was within 3-4 pounds of the originals and the rate similar, perfectly compatible with the motor’s flat-tappet cam.