Rotec
Hi, Congratulations on your RV8R build to date. I have a fair bit of time behind the Rotec R3600 in my Spacewalker, and have had a number of discussions with Brian during and after his fitting the Rotec to his RV8.
There are a number of little differences between the Lycoming and the Rotec, particularly the oiling system, and replacing the 3/8" feed and scavenge lines with larger 1/2" ( -8) and replacing the banjo fittings on the pumps with high flow 90 degree items will drastically improve oil pressure throughout the operating range. I thoroughly recommend these mods.
I see you have gone with longer gear legs, as I did on the Spacewalker ( 9.5" longer) and still had to use a max of 78" diameter prop. I love the look of the longer legs and the more aggressive stance, and you may do too. It will be interesting to how the 8 performs with the large diameter prop.
I see that Brian has changed over to a Verner 9 cylinder radial, but haven't heard anything on how it performs since the initial video was posted.
If you have any queries, I am happy to help in any way.