From 1985 to 1986 the engine used a hemispherical head carbureted design.
Hemispherical chambers have never been MOPAR only - they only have a trademark on the Hemi name. It's just kind of funny to find it in the 3-banger G10.
I wonder if I could find one and swap it into the Metro? Hmmm...
Yeah, I'm guessing that's what they mean by cooling, the hemispherical design was too prone to detonation or something such.
I can't think of another reason they'd design such an oddball engine and only use it in one model for two years, but I guess US engineering doesn't make sense a lot of times.
I'm saying that US manufacturers will do silly things like run an engine design for only two years.
But Geo is japanese stuff, though I dunno how much was the designers' decision and how much was the US office's. I dunno, I'll blame it on a detonation issue that seems implied in the "cooling" statement.