SPEEDMASTER ALUMINUM HEADS

Got several sets. Two sets in use on bracket cars. One set ported by IMM in Indio ca, that 360 has run in the 10.50s in Las Vegas. Second set was their CNc head with valve job done by local machine shop. That car has run 11.40s, should run faster this weekend. Nothing is the heads fault.
Would you mind giving details on the engines? I’m building a 360 using the IMM heads and was wondering what I can expect. Thanks