The first problem here *I think* is that you mentioned you have R/T heads. The create engines did not come with R/T heads but regular heads. If your head(s) do not have a R/T cast into it, the. They are regular heads.
The last run of crate motors had the R/T head because Mopar stop casting the regular Magnums.
Head work would be my first thought. Maybe some Roller rockers. It depends on were you want to gain power, Down low ? Up high ? Mid range ? Maybe a converter or gear swap ? Whats your exhaust and ignition. Ive seen those crate 360 run 11s out of the box with the right chassis.
