Engine Bay Rebuild - Motor Mount Blocks??

[76SeaRay]

So before I commit to wood and fiberglass, I am looking for opinions on the replacement. Here are pictures of the original engine (Windsor 351) and the empty engine bay that held it. The motor mount sat on top of a piece of 1/2 inch plywood and lagged to the bay as you can see in the second picture..

Original Engine in Place (OMC Stringer Drive):



Empty original engine bay:



Should I rebuild the bay with as shown in the original and then simply add blocks to shim the engine up for the new GM 5.7L mounts in the following pictures:



End view of the height increase to set the adjustable motor mounts to mid-travel. Although not aligned perfectly the alignment tool slides in and out fairly easily with the motor supported as shown:

 

[JASinIL2006]

My boat was repowered before I bought it, and whoever put in the engine (a 350 Mag replacing a 4.3), used shims under the front motor mounts. When I restored my boat, I didn't need to remove or rebuild those mounts, so I kept the shims. (I think the shims may be Starboard, but I'm not entirely sure; they are some sort of dense, white, synthetic material.)

You do need to make sure your shims won't compress or rot, and your lag screws for the mounts must of course be long enough to firmly attach to the mounts under the shims, but it can work.

Of course, if you're rebuilding the mounts, just build them to the desired height to start with.

 

[76SeaRay]

I would probably either get a single piece and fiberglass it in or laminate marine grade plywood.. The original had like one or two loose pieces of 1/2 inch plywood between the mount and deck step.