1998 Z242 with 7.4L Bravo3 orig prop spec
 

Does anyone know what the factory prop size was for this setup? When I bought is used 10 years ago i think it had 28P and was doing approx 60mph but after having them reconditioned at WOT max speed is 51mph at 4,000rpm. Guessing they changed pitch when the reconditioned them or gave me someone else's prop and maybe even a different pitch. I purchased a used set of 26P Bravo 3 props on e-bay and at WOT max speed is 53mph and 4,500RPM. Thanks for any help anyone can provide.