75 torino really ?

What is your hull number. Usually, the hull number gives a clue as to the model year. I think the 351W should not turn more than about 4800rpms, but I have no idea what a Hallman Mooney really is and 5000rpms might be ok. Why do you want to run it that fast anyway? For me, I never take my rpms much past 4000 and when I do, it is rare. Just because it will, does not mean you have to. The longevity of the engine will thank you if you keep the revs reasonable.

OK now Wally. Are you sure you didn't mean the higher the pitch the lower the rpm's?

As for the boat, does it look anything like that Separator in '75 brouchure? Maybe it could be a 71-72 or so, so check those brochures if available or if you haven't already. Check the Holman Moody I.D. tag on the bellhousing and the code there will tell you what year model the engine is, as they used the Ford coding system. And then for sure, do like David said and check the hull number. If it's stamped into the gelcoat on the transom, then the last two digits are your year model. If it's on a plate affixed by the throttle, then take the number and call Correct Craft. As for engine speed, 5000 is a bit high according to the Holman Moody literature for a stock engine, but at the same time I wouldn't think that a stock 351 would turn a 12x18 5000 rpm, so you may want to check the tach as well before you invest in a new prop.

thanks for the info guys

I dont think its good to go over 4500 rmps either.
there is no hull # butI did find ser #
Tag on bell housing = EOHM -4166 2-RW
                      CPM 290-4V C9HM MF2
                      CR 9.5 .1 TIM 12'
Tag on intake = 351W 70 4
               A15 K207 -A66
Does anybody know # ?
I guess i should call C.C.
My boat does look very similar to the 75 separator.
I will post old brochure I found on the diaries