Check engine mount for fit around starter. It may be necessary to install engine without starter as the fit appears quite close. Install .018 GA 304 SS firewall and match drill engine mount attach holes. Install engine mount attach bolts. Upper mounting bolts use self locking nutplates affixed directly to aluminum angle reinforcing.
Lower bolts use standard elastic self locking nuts over an aluminum backing plate.
My hovercraft is full of eels. Firewall steel was cut to fit and installed over the fiberfrax and secured using 4 small sheet metal screws. Re-install brake master cylinders and lines. Size bolts for engine attach. AN7-35 for Revmaster on Rand Mount.