Aluminum heads make this a lot easier as they move heat faster so are forgiving of missing compression ratios to the higher side and squish/quench clearances also to the higher side.īoth of these cams are pushing the factory 元1 heads pretty close to their lift limit without guide work, you'll have to measure this once you have the heads in hand. The iron 元1 Vortec would work on either but more attention would have to be paid to being spot on to. Since this isn't hugely different from cam number 1 probably most of the bottom end can be restored with raising the static compression ratio from a half to one full ratio but that can make the upper end more detonation sensitive requiring a higher grade of fuel or other compromises to timing and lowered operating temperature all of which drag mileage down or drive operating cost up.īoth of these depend on modern heads. This pushes the power curves up to a higher RPM at the cost of bottom end torque and increased fuel consumption.

This keeps, on the intake side, the valve off the seat longer so there is more reversion of mixture being pumped back out of the cylinder by the piston rising on the compression stroke. 050 lift measure and total lift but it has a lot more duration devoted to ramps. The first cam will build a more efficient engine and deliver a good wide power band peaking around 300-330 hp with moderate compression.