Slant 6- v8 centerlink

I would stay <1" spacer on the motor mounts, since raising the engine leads to other issues. You probably need only 3/4" to clear the slant center-link. Other issues are that the fan may hit your radiator shroud, especially since 1" at the mounts extrapolates to ~1.5" at the fan if you don't also raise the tranny mount. Less hood clearance. The angle of the driveshaft will change, which can cause vibrations if you don't change the "pinion angle" of the differential to match. I recently tried installing hydraulic motor mounts (~2002 Corvette) in my 1985 M-B diesel and the 1" increased height was unworkable (plus made engine vibrations worse).