I have purchased a 1987 Pachanga 22. I picked it up in a low altitude state and it ran 63 on the speedometer with a 23 pitch prop.
I got it home and took it out on the neighborhood lake at 6000 ft elevation and it wouldn't come out of the water.
I live in a small town so I took it over to the largest boat shop we have an they told me I have a low altitude prop and I need a 20 degree prop.
Long story short... I did 57 mph at 4700 rpm with the 20 degree prop.
Am I stuck going 57 mph with my Pachanga? Or can I do something else to increase my top end speed?
I would think the BBC would spin a 23p no problem. also I wouldn't trust the speedo. I'm with RSCHAP I would think your carb would be the culprit more then your prop. p.s. nice pachanga, I'm not sure, but I think I've seen that one somewhere :bigsmile:
I have the edelbrock as well on my SBC. In the instructions and tuning manual there is a section on high altitude use. Remember its not going to be as fast no matter what you do. Theres an article in hotboat this month about a guy with a merc bbc and a blower. Mercruiser just told him to run more boost to compensate.
FWIW, when I take my p-22 from the bay area up to lake tahoe, I swap out my 23" bravo 1 stainless for a 20" intimidator 4 blade, or I can't get out of the water even with a custom racer built HP 500 MPI. I also lose about 10mph of top end at the same rpm's as sea level. Average elevation of lake tahoe's surface is 6,225'. So I'd expect you'll have to swap out the prop and you'll see the boat respond similarly to mine.