Dwayne is a nice guy and very helpful here. With your 500 12.25:1 Dwayne will probable spec you something in the low to mid 260@50 max effort street/strip. My Dwayne spec'd 270@50 for my 11.25:1 511 was too much for the combo and it showed when I raised the compression to 12.5:1 as it really woke up. Another plus going thru Dwayne is you would always have him here for questions later.