Sorry about that. Yes a 750 Mighty Demon. On engines that idle at or above 1000 RPM you'll open both the primary and secondary butterflies the same amount. On your engine that idles at 900 RPM you'll open the primary butterflies to about .020" of the transfer slot, and set the secondary butterflies to the bottom of the slot. As far as the spacer goes we'd recommend using either an aluminum, or phenolic, not wood.