Your motorhome heads may even have the exhaust rotator springs and retainers(which do not like any enhanced performance upgrading).With the amount of top-end removal you are looking at I would just pull the heads and go-over them.If your guide wear isn't bad you should be able for relatively low-bucks throw in some good springs,locks, retainers and seals.Measure retainer/guide clearance and if you have the adjustable rockers already definately look at a solid cam.