Will a 2.5L Super Duty head fit a standard 2.5L?

In a word, yes.

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84SE w/ T-Tops

Please, someone elaborate on this. Why don't we hear more about Fieros with the Super Duty 4?

Welcome to the forum!!

As was already posted the standard SD-4 head (large port) will fit. There are a couple other choices as well. An aluminum head and Cosworth made a twin overhead cam head for the SD engines. Not sure on where to get the Cosworth or if it fits without modifications. You can get alot of information by doing a search for 'super duty', 'SD-4', 'cosworth' etc.

Some of the parts like intakes and such are still available See the listing at https://www.spoperformanceparts.com/store/catalog/Category.jhtml?CATID=1124

Why don't you see more about the SD-4. In a word....Money. The SD-4 is a race engine that will set you back about 8 grand US$ (new). Most people will just drop in a V8 instead.

David

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His Fiero: 1984 2M4 Coupe

Her Fiero: 1984 2M4 Convertible

SD head fits but then the intake won't. I had one in 84. Improved performance somewhat. Would recomend the hooker header for Fiero if you can still find one. I still have the SD 2bbl manifold sitting on my shelf never been on a car yet.

Any SD-4 head will bolt up to a stock block just like an SD-4 crank will fit in a stock block. To bolt an SD-4 head to a stock bock the bock needs to be drilled and tapped for a larger bolt. Don't remember the size off hand. If you use an SD-4 head you need to use an SD-4 intake just because the ports on the head are so large. You can use an SD-4 intake on a stock head as well. Check out my site in my profile. There is some infomation as well as pics. You can see th difference between two SD-4 heads, a stock fiero head an a Citaion head.

The Stickman

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http://members.tripod.com/~TheStickman/SnTsFieros.html