Nope, two different bolt patterns.
Some older kart guys were using 4HP heads to bump compression, but it was said that it actually hurt performance by shrouding the valves. If you want to bump up compression, have a stock head milled or just buy one on eBay. I have done it myself with some sandpaper glued to a piece of plate glass, but it takes a while!
BFH (Big Flippin Hammers) is what I used before the internet! I may have some extra 5HP heads if you want one to play with! ...but because you're in NY, the shipping is more than the part. Your local small engine guy should have some!
I now have a total of 7 engines. Pretty much seems they each have an issue of some sort. Would it be possible to throw them into a big blender and whip for about 10 minutes and possibly end up with 1 or 2 good ones? No I have not been drinking, yet!