David wrote:
"Clyde,
I've never seen OMC/chevy four-banger engines, just Mercruisers, but they are sweet little engines and I guess anyone could use 'em for small boat power. I'd like to know more about the OMC applications."
This is the nearly the same engine as the Mercruiser. GM built the 153 cid for automotive, marine and industrial applications. It is (was) sold to marine and industrial customers without an intake or exhaust manifold. GM quit using it for cars and light trucks around 1970. The engine then evolved to the 181 cid (3.0 liter) in the mid-1980's. It is the same basic block but the bore and stroke is changed...from a 3.875" x 3.25" to a 4.0" x 3.6" stroke. In 1989, the rear 2-piece seal went to a one-piece seal similar to a GM V-8 engine. In 1998-99, the head design was changed to make more power. A throttle-body injection system is an option too.
The performance version "Iron Duke" is actually the GM-Pontiac Superduty-4 race engine. It shares a few characteristics with the 153 and 181 but is closer in appearance to the GM "R" street engine installed into the rear-drive Chevy Monza and Pontiac Fiero.
GM discontinued the Superduty-4 engine but an improved version is now made by Kansas Racing Products. It is much stronger than the 153-181, the OEM "R" engine and the old Superduty-4. The new block is more versatile as it accepts most V-8 small block cylinder heads...GM, Ford or Mopar.
Regards,
Gerry Dedonis
Kansas Racing Products Inc.
http://www.kansasracingproducts.com ------------------
