Does the colored powder coating on the juggs help with cooling, heat dissipation?
Mark, any difference is minimal. The original powder coating is removed before the new goes on. So while the new coat may be slightly thicker it's not as extreme as one might initially think. In this case it's a two stage powder/clear so, again, a little additive difference. Not extreme though.
The other engine I did in this way I was curious about. So took a few temp measures on different days before disassembly and kept track of the data. Then after the engine was built took measures again on days of comparable weather.
In the before and after comparison I did see slightly more heat. In comparisons that were admittedly difficult to keep precisely even I did see that slightly greater heat after those rides that were as comparable as I could make them. Even then, however, I could not blame all of the relatively small difference I saw on the powder coat work since part of the engine work included work that raised the compression and changed other factors in the engine that, by themselves, would have generated more heat/power.
It'll be the same with this one. Going from a basically 95" engine with a small cam to 98" with compression up around 10.2:1 and the 625 cams. Even if the stock powder coating were still in place the engine would generate a little more heat.
My only actual concern with the heat question though is that the first generation SERGs didn't come with an oil cooler. I've never had reason to add one. With this bit of engine work it's something I might end up doing.