I have my stage 1 RXP with following mods

Riva Power Filter
Riva Vortech SC wheel
Solas 14/19 repitched ny jerry
Riva Grate
Riva Sponsons
IXU 27 Plugs
Skat triple bearing pump

Last GPsed I was at 72.3 mph, and If I add a RR SC and 42 lbs gians what gians should I expect ???