Like Vortec heads, E-Tec intake ports are 0.200-inch taller than conventional Chevy heads, and use the Vortec intake bolt patternfeatures that mandate a Vortec-compatible intake manifold. E-Tec heads accept standard or center-bolt valve covers. Check out the details in the sidebars below.
GM small-block Chevy Vortec heads deliver great performance per dollarbut theyre still only based on production pickup-truck castings. The iron heads are heavy. They have press-in rocker-arm studs that can pull out under high spring pressures. The valvespring retainers hit the guides above 0.470-inch valve lift. Late-model guided rocker arms are mandatory. Only center-bolt valve covers bolt on.
Enter Edelbrock. Its new E-Tec heads retain the best features of the Vortec configuration but are set up for high-performance use. They bolt in place of Vortec heads and accept Vortec intakes, valve covers, and valvetrain parts. They are also compatible with standard perimeter-bolt valve covers, high-lift cams, nonguided rocker arms, pushrod guideplates, and screw-in rocker studs. And theyre aluminum, so they weigh almost half as much.
Two different E-Tec cylinder-head configurations are offered: the E-Tec 170, designed specifically to replace iron Vortec heads; and the E-Tec 200, big Es answer to GMs aluminum Fast-Burn heads. Both incorporate new high-quench combustion chambers that yield more uniform air/fuel mixture atomization for added power. The spark plugs have been positioned closer to the center of the cylinder for more efficient combustion. Complete heads come with 1.46-inchod valvesprings that can handle up to 0.575-inch valve lift. Fully assembled, a pair of E-Tec heads weighs just 55 pounds34 pounds less than a set of Vortec heads.
Car Craft had Westech Performance wring out the new E-Tec heads on a low-compression, stock, rebuilt 355ci small-block equipped with an Erson TQ40H hydraulic flat-tappet cam (intake/exhaust specs: 0.503/0.503-inch valve lift with 1.6:1 rockers, 218/228-degrees duration at 0.050, 110/110-degree centerline, 110-degree lobe displacement angle). The heads were sealed with Fel-Pro heavy-duty partshead gasket PN 1043 (8.2cc compressed volume), designed specifically for Vortec-style chambers; and intake gasket PN 1255, which has a Vortec intake manifold mounting-bolt pattern and matches the taller Vortec intake ports. Both were tested using an RPM Air-Gap Vortec dual-plane intake (PN 7516), 750-cfm Performer square-flange carb (PN 1407) with optimized jetting, and headers with 1-¾-inch primaries and 3-inch collectors.