I'm currently running a FG84 in a TF Corsair that was modified by Ray English. He had a big problem early on but since it was fixed the engine has run strong. My main concern now is enough prop to bring down the revs in flight because compared to static rpm it's unloading as much as 1500rpm in flight.
So so if you want the new FG90 then I suggest getting telemetry on the rpm so you know what it's doing and you keep the revs in check.
Otherwise the DLE 55RA and the 61 are the way to go. I flew this same Corsair with the 55RA fr a while and it's fast and sounds great. If you go this way put a Xoar 22x10 carbon prop on the 55RA.
Ill be testing the DLE 61 with a 24x12 later on in a TF P-40. Either DLE engine you can't go wrong.
If you have to have a 4 stroke then another option is a Roto motor. Look at the CAD drawings they have to see which engine fits the cowl diameter.