Iron duke question

[mudkicker715]

Not iron duke but chevy 151. Looks just like my inboard outboard omc, which has a chevy 151.

[BenM]

It's definitely an SBC pattern, and it has the lifter-cover. I'm thinking a pre-crossflow 70s head. Maybe someone had one sitting around for a rebuild?

[mudkicker715]

It's definitely an SBC pattern, and it has the lifter-cover. I'm thinking a pre-crossflow 70s head. Maybe someone had one sitting around for a rebuild?

Not necessarily. My inboard outboard omc boat is a 79.

[captspillane]

I digged through a box of reciepts that came with the car. Two of them were from a parts store that listed the car used as a search tool. It said 1978 Chevy Monza. If thats the car the engine came from, it is an Iron Duke with a different head casting.

I've never even heard of a "Monza" before. There isn't any for sale on ebay for me to sneak engine pics from. It seems that some earlier Iron Dukes share a similar head as a SBC with the intake on the same side as the exhaust. I haven't been able to confirm this.

I absolutely love that I can see the fuel pump and that it has an HEI distributor in easy view. Our Eagle Iron Dukes are incredibly cramped on the passenger side.

[captspillane]

I think right now that the engine is actually a marine engine. I think the Monza had the carb on the same side as our Eagles did. The other possibility is a SBC Head. Here is a link to a Monza forum where they discuss precedence of people using a SBC head on an Iron Duke short block.

In this thread they also mention GM marine engines being readily available with a displacement of 181. It would be awesome to know if the GM 181 marine engine will bolt right in to replace an Iron Duke. Indeed thats what I might have in this Kammback.

They also mention that it would be non-crossflow, which I take to mean the intake and exhaust on the same side, which matches what I have. The exact quote was "Just a note, that is a " non crossflow " head that will work on the 68 - 70 Nova 153 and the H Body 77- 78 151." If "H body refers to Monzas, then maybe it is indeed a 1978 Monza and only those two years have this head design. The Monza pictures I found didn't show an engine like mine.

http://forums.h-body.org/viewtopic.php?f=2&t=916&start=45

[captspillane]

Mystery solved. My Kammback has a 1978 Chevy Monza engine in it.

The Iron Duke was first offered in 1978 to replace the 1977 Vega engine. The all aluminum Vega engine had a very bad reputation, so the name "iron duke" was meant to keep people from confusing the new engine with the old. In 1977 and in 1978 the Iron Duke had a non-cross flow head and Holley carb. It was 1979 that the crossflow head and Rochester carb appeared. The block and camshaft was slightly different too, since the distributor was closer to the center of the engine. The Iron Duke is essentialy half of a Pontiac 301 V8, to the point that all the bearings are the same and even that a V8 head will bolt up.

What I've learned alot about just now is the Iron Duke marine engines. The 2.5L marine engine gets a true 120 HP while the 3.0L Marine Engine gets a true 140 HP. Mercruiser 140 is another name for the 181 3.0L engine. Thats a huge difference from the automotive rating of 80 HP! The 181 engines are apparently extremely common too.

The best part is that the 151, 153, and 181 all share the same bolt patterns. In other words a 3.0L Iron Duke marine engine is a perfect swap candidate for an Eagle. Notice that the marine engines are not cross flow, they have the intake on the same side as the exhaust like this Monza engine.

The new S10 Iron Dukes sound great because they are fuel injected, but it turns out its the 181 marine engine adapted with megasquirt thats the ideal Iron Duke race engine. The S10 Iron Dukes never came close to 140 HP. Thats great news for us, since this means the ideal Iron Duke has the same bellhousing and motor mount pattern as our Eagles. Even better, its readily available for cheap. I can't believe this hasn't been discussed here on the forum already.

[rollguy]

The new S10 Iron Dukes sound great because they are fuel injected, but it turns out its the 181 marine engine adapted with megasquirt thats the ideal Iron Duke race engine. The S10 Iron Dukes never came close to 140 HP. Thats great news for us, since this means the ideal Iron Duke has the same bellhousing and motor mount pattern as our Eagles. Even better, its readily available for cheap. I can't believe this hasn't been discussed here on the forum already.

The S10 engine would have the wrong bell bolt pattern as well.  Eggs to you for the marine engine info!