Head gasket question

This destined for a 318
What's the difference between the fel pro 17050 "marine" head gaskets and the regular "car" ones?
I know fel pro also has a "heavy duty" head gasket version too. Somehow the "9898" part number ( actually spec'd for the 360 I believe) comes to mind.
Daily driver, small cam, build along the lines of the "very mild 360" thread build.
Are there different holes in the marine gasket that aren't in the pass car gaskets or vise versa? Made from different material? Different thickness?
Any reason "Marine" head gaskets won't work for a 78 block that's getting '302 heads?
Or even if they will work any reason why they either should or shouldn't be used?
Found some on eBay and had one on my watch list and they sent me an "offer"
Their listing price was $40 with free shipping, they sent me an offer for $30 shipped. Unfortunately only one at that price. I bought it and another that was $40 shipped from someone else. Seems nobody has more than 1 but there's 4 or 5 people selling 1 here and 1 there.
Some for lots more.