460 cui. ford exhuast manifold gaskets, in a 1994 class A moterhome R/R?

[comunityidiot]

had backfiring out of exhaust, took to service garage they told me exhuust manifold gaskets were leaking. to replace them would be very costly because ford used exhaust manifold bolts that were designd to not back out after they were tightend. the chance of them breaking very good if can'nt get them out may have to replace heads. i put headers on other cars is this thing that much of a nightmare.