On the other hand, there are several tried and true STCs for larger engines for both 180s and 182s. If you assume a 230hp Continental actually has 230hp at sea level and all of the various conversions have their advertised horsepower at sea level, a 260hp conversion will still have 230hp at 4000'. A 285hp conversion will still have 230hp at 6500'. A 300hp conversion will still have 230hp at 7700'. There's a lot to be said for the simplicity of a normally aspirated engine, in terms of maintenance and longevity.
Be aware, also, that adding power doesn't translate into a whole lot of added speed with the draggy airframes of these airplanes. They'll climb better, but there's not a lot of extra speed to be had, unless you also go for various mods to reduce drag--and those aren't necessarily as good as their vendors say that they are in terms of providing much extra speed. A 130 kt airframe with a bigger engine might become a 135 kt airframe, and add some drag-reducing mods to the tune of several AMUs and you might make 140 knots. But the difference in block to block times won't be dramatic. For instance, let's say you want to make the typical GA cross country trip of 300-350 miles. At 130 knots, it'll take you 2 hours 20 minutes for 300 miles, 2 hours 42 minutes for 350 miles. At 140 knots, you'll reduce those times to 2 hours 9 minutes and 2 hours 30 minutes respectively. Is saving 11 or 12 minutes for the typical cross country flight really worth the financial cost of all that extra power?
Cary