[MrPbody]

Old Lar,

The "Iron Duke" began life in 1960, as "153", in Chevy II. It's essentially the same as the Chevy straight 6 (230, 250) with two cylinders lopped off.

It was used through at least '68 (a friend had a '68 Nova so equipped). It also found a home in the smaller marine applications, and is still in production today for that, along with the 3.0 lr. version (181).

By '76, it was obvious Vega wasn't going to "cut the mustard", so they (GM engineers) looked to the old engine. They redesigned the head (a little) and made it all "metric". The 151 CID "2.5" Iron Duke was born. They used the name to be sure no one thought it was the Vega POS.

In '79, the "cross flow" head was introduced, dramatically improving higher-end performance. All the '80s 2.5s were this design, with small variations for FWD and RWD applications.

When Fiero became more popular than expected, Pontiac started a racing program for the engine. The 2.5 SD is a KILLER version of this engine. You can find them in total domination of the "Goodie's Dash" series. NOPI outlawed 2.5 AND Quad-4 immediately, as the Japs have no answer for those two engines. They (NOPI) allowed the Saturn 1.9, but at that time, no other GM engine... Maybe someone reading this can update the info.

Just wanted you to know a little more than the "commuter engine" history. Iron Duke is a great engine! The lack of periodic maintainence is usually the culprit if they die an early death. Fiero's smaller oil pan accellerated the issue.

Jim