Just obtained a 1962 Thompson Bros. lapstrake boat with stern drive! The engine is a 6 cylinder. A tag indicates Mercury, Kiekhaefer Corp, serial number 1631704. Cast into the block at another location is: CM (might be GM) 377127.
Wondering what year this is? Is it 1962?
Pic of tag on newer outdrive:
The outdrive is much newer. MerCruiser serial number 5074345 and on the outside it indicates "470" and numbers 6030107 1-84R
I don't know if you got my email response yesterday, I was having computer issues for a bit.
The engine is a 1962/1963 194 CID 140 HP. If it runs, use it & treat it carefully, be sure to winterize it well.
The drive, transom plate & trim system is late 70s to 1981 vintage. From the serial number, late 70s. 1.84:1 ratio was the standard ratio for a 170/470 engine package.
You can substitute a 165 HP inline from 1970 to 1979, it will bolt in maybe requiring minor wiring issues. I would stay away from the 150 HP 230 CID inline 6 (1964/1966) and the 160 HP inline 250 CID (1967 to early 1970) simply because the manifolds are hard to find. There were tons more 165s built & manifolds are still available.
Serial number breakdowns for MerCruiser inline 6 engines:
140 HP 194 CID s/n 1538930-1725960
150 HP 230 CID s/n 1666495-2048043 notice an overlap with above
160 HP 250 CID s/n 2048022-2770031 notice an overlap again
165 HP 250 CID s/n 2770032 and up
Just a note, there was a 200 HP 292 CID GM truck engine used in 1969 & it was mated to a MerCRuiser 2 drive. This is a rare engine, it is taller by about 1 inch and very strong. It was mated to the #2 drives because the #1 drive of the time period wouldn't take the power.
I've been trying to "self tutor" on the I/O Mercruiser stuff too, Andreas. You might find this "How do I ....." stuff helpful, I sure did.
(No substitute for the experienced help we get from the gang here, but worth a look anyway?)