Car Craft Engine Build & Comparison - Battle of the Titans: Chevy 350
Photography by Terry McGean
As mentioned, we wanted to get the maximum compression out of the combination, so we used Fel-Pro's 1094 head gaskets, which are rubber-coated steel shims that have a compressed thickness of only 0.015 inch. A typical composite gasket would be about 0.042 inch. These gaskets coupled with the Vortec's 64cc combustion chambers and the 5cc valve reliefs of the Speed Pro pistons, plus the 0.024-inch depth of the pistons, should give us 10.4:1--just about as far as you'd want to go with iron heads on pump gas. This approach will also allow us to reduce compression later if necessary by simply using a thicker head gasket. Milodon head bolts provided the clamping.
We thought about investing in 1.6:1 roller-rocker arms (1.5:1 is stock for the small-block Chevy) but found that the increased valve lift wouldn't work with our Vortec heads and this particular cam. We could have gone with 1.5:1 rollers, but the Vortec heads require self-aligning rockers, which should also be a narrow-body design to clear the center-bolt valve covers. Crane offers the perfect solution in its Gold Race Extruded line (PN 10751 for 1.5:1, PN 10758 for 1.6:1), but they cost $310, which seemed extravagant for our meager budget. Instead, we went with a fresh set of stock GM stamped-steel self-aligning arms. The set of 16 new genuine GM rockers complete with new balls and nuts was only $50 from Scoggin-Dickey.
The cherry on top is the Edelbrock RPM Air-Gap intake manifold. Our rules stipulated a dual-plane design, and the RPM line consistently shows excellent results over a broad range of engine rpm. The Air-Gap makes that even better by separating the intake runners from the base to isolate them from the engine's heat. When we get to the dyno, we'll mount the same 750-cfm Road Demon carb that was used on the other engines, along with a set of Hooker long-tube headers and an MSD distributor.
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