Alpha One Vintage

I bought a 1974 boat with a 23

I bought a 1974 boat with a 233(Ford 351W) and was told the leg was replaced about 50 hours ago which is likely to be 5 years ago as boat has been sitting for 3 years. Was told by a marine mechanic at local marine shop that this boat would have come with a MR model leg originally. I would like to try and narrow this model down as the gen 1 or 2 and approximate year range for future reference if needing parts.
On the starboard side of the upper housing right under the nameplate there is the following stampings. Left portion says 150R and under right side of label it appears to be stamped.0B538835 or 0B533835. I presume the 150R is referring to the gear ratio. Any clarification appreciated !!
Thks

"I may have answered my own qu

"I may have answered my own question. It appears that the serial number (if I drop the 0 in front) indicates the following : That outdrive is used from 87/95 in everything from a 2.5 inline 4 to the 350 mag (5.7L GM) and the only difference would be gear ratios matched to engine and boat size. I would still like confirmation that I have got it right and wondering if the 1:50 ratio seems right with that motor in a 24 foot Fibreform command bridge model.When trimmed out properly, the boat does 32 mph at 3200 rpm."

1992 was the change year to th

1992 was the change year to the GEN II drive. It's unlikely that it is a GEN II in that the transom assembly would need to be changed. The easy way to tell is the shape of the lower half of the unit and the bolts holding the lower half on. GEN II the skeg is angled in towards the the centerline and the ALPHA I is straight. Also the GEN II lower is held on by nuts and bolts where as the ALPHA I has studs in the lower and not bolts. Difference between MR and ALPHA I is MR has a lifting ring on the top cap and the cavitation plate is rounded. The ALPHA I top cap is flat and the cav plate is sqaured.

3200 max rpm is low for a sterndrive. Max should be around 46-4800 rpm with a cruise at 3800. You may be over propped. Prop size on a boat is entirely up to the driver to the extent that if the boat planes and handles well you use what you are comfortable with. You may plane out and get more speed with a lower pitch but it's trial and error. Most prop shops I have delt with will allow you to use a prop to see what you like if you don't bang it up. 1:50 is the gear ratio of choice for a 351 v-8. This will keep the max prop shaft rpm in the correct range.

"Thanks for the reply, boatrep

"Thanks for the reply, boatrep. As I stated before, this boat sat for 3 years and had a full tank of 3 year old gas.Boat started and ran reasonably well considering the gas but wasn`t pumping much water so decided to change the impeller and ended up replacing the wp housing as well because the bushing the impeller rides in had shifted and was kind of cock-eyed in the housing.
Next , decided to take the boat out and see how it ran on the water and hopefully burn up some of that gas. I have smelled old gas before and was surprised this didn`t smell too bad at all.
I have no idea what the WOT rpm`s on this boat will be as I simply ran around for a couple hours and never took it over 3200 rpm.
I then gave it a complete tune up , changed oil, filter, water seperator filter and change the lube in the leg.
It`s going back in the water tomorrow morning and we`ll see how it performs with the prop it has. I hope the wot rpms are where they belong because I got 4 props with the boat. "

"I took the boat out this past

"I took the boat out this past weekend and it`s wot rpm is about 4000. According to the selco manual under the tune up appendix , it says that wot rpm for this model is 3800-4200 rpm ."