? 'bout chevy SBC police cast#

fellas Iam looking at a 50' deluxe with a SBC '73 chevelle update, the gentleman refers to a police designation on the engine but I can't find anything in my chevy books , does someone know thanks.

 

http://www.mortec.com

 

They had some suffix codes the were used for police/taxi /HP
they were 4 bolts Im sure but I dont think anything really special or not any better than the other HP applications

 

Thanks tchurch that links has some good stuff, he mentioned CM or TM i'll check it out thanks fellas