Re: 250/292 inline six
Howdy,
When I had my 66 Marktwain with the 150 Mercruiser (230 cu-in I6),
I researched extensively the differences between the 230/250/292 and found that most parts will fit. Even the cyl heads are completely interchangeable. (each head on each engine does produce different compression ratios)
In 1966 Mercruiser did offer a 292. The engine mounting scheme was somewhat different from the 230. I had a service manual for it and I believe the HP rating was 170 or 190hp.
The differences with the 292 was mainly the engine mounting, deck height and the size of the harmonic balancer.
It appeared that the harmonic balancer might not fit with the front engine mount that came from a 230/250 engine even though it might bolt to the block. Some blocks did not have the mount points for the Mercruiser mounts.
My plan was to use a 292 block and 250 marine manifold. You would have to deal with the 1" or so higher cyl height. It would require you to adapt the exhaust elbow using a longer piece of exhaust hose.....probably not a huge deal....
I changed my mind to a 250 since the front mount would have interfered with the balancer. (unless you could find/fabricate a different front mount.
It's probably not worth it since there's a lot of ways to "speed tune" a 250, one of the BEST marine engines ever made for a small boat!
If you want to know more about inline 6's, go to
http://www.inliners.org/ they have a lot of people there that have done a lot with all Chev and Ford sixes.
Cheers,
Rick
