9.5:1 on the Aluminum head cars. Had 8:5:1 on my stock steel head 318. All run plates to allow 18 degrees idle and 30 all in. Cams are all low duration hitting around 7.5 dynamic and 185 PSI cranking (the cast head build was lower) My car with the stock cast heads and low compression pinged like a bugger and struggled with over heating in traffic. Both the aluminum head 318 and 360 have never pinged and run cool. All radiators are 4 core done by GlenRay.
