TFS-R Cylinder Head Install and Test - Trick Flowing Casts - Tech

To illustrate what the new heads had to offer, we installed them on a 428 stroker. What better combination could there be for the impressive head flow and large port volumes than a large-displacement stroker? The 7.0L motor started out as a Dart Windsor block equipped with 4.125-inch bores. This motor was further bored to 4.128 inches to accept the forged reciprocating assembly from Coast High Performance. The CHP stroker kit included a steel 4.00-inch stroker crank swinging a set of forged I-beam rods and flat-top pistons. The pistons featured dual valve reliefs for use with both inline and TFS valve locations. The combination of the 4.128-inch bore and 4.00-inch stroke produced a final displace-ment of just over 428 ci. The 428 was equipped with a custom solid roller cam that offered near 0.680-lift and a duration split of 246/251 degrees at 0.050 with a 109-degree lobe separation angle. The roller cam featured aggressive ramp rates to maximize opening time of the cam relative to the duration figures. The Comp cam was combined with a double roller timing chain, 1.6 ratio roller rockers, and custom-length pushrods to work with the R heads and roller lifters.

The remainder of the stroker included the CNC-ported TFS-R heads installed using Fel-Pro gaskets and ARP 11/42-inch head studs. The R heads were topped off with an Edelbrock Super Victor intake, a Holley 1,050-cfm Dominator carb, and a Wilson adapter. Also employed were 131/44-inch Hooker headers, an MSD ignition, and a CSI electric water pump.

Since the short-block had been run previously, there was no need for a break-in period, and we immediately filled the crank-case with Lucas 5W-30 synthetic oil. The 428 sounded plenty stout with its 12.0:1 compression crackling through the open headers and collector extensions. After tuning the Holley Dominator carb and adjusting the ignition timing, we were rewarded with peak power numbers of 674 hp and 589 lb-ft of torque. You'll remember that the airflow/power formula suggested the heads were capable of sup-porting 700 hp, and we see no reason why this motor wouldn't produce 700 hp with a more aggressive cam profile, a ported intake, or even by experimenting with something as simple as carb spacers. Where the as-cast TFS-R heads were impressive, the new CNC-ported versions from TFS take them to a whole new performance level.