I got mine from Hamilton Marine, but I believe they're readily available from a lot of retailers.
https://shop.hamiltonmarine.com/product ... 25635.htmlThere are multiple choices. I suggest 1/4" aluminum bars or G10 strongly mounted/bolted on the existing beds first and work out proper placement of new mounts to avoid side stresses. Overall it isn't a huge chore. I used a scissor jack on plywood with padding to lift.
Edit: I'd go w/3/8" to 1/2" aluminum stock or G10 on the engine beds. This allows you to line up and re-drill the engine mount holes to avoid side stresses. I used the old holes and they weren't quite right. I notched out 3/8" G10 to slide under the aft mounts to get some of the thread back on the studs. The old mounts were adjusted quite high.