Ive ran 12:1 on pump gas without any issues.... But pump gas varies from state to state, your camshaft will play a large roll in bleeding off some of the cylinder pressure... I usually use pumping compression for a good indication for pump gas. Ive seen multiple engines make a 1000 hp on pump gas naturally aspirated. Both were close to 600 inches.

Last edited by cuda499; 10/21/20 02:06 PM.