Correct me if I am wrong here but you are going to place 2 walls on the outside of the boat and lift 454's from 4 2x4 supported on these 2 walls? What is the center span you are looking at to me it seems like you will have a span of about 11 or 12 feet? Is this correct? If so I wouldnt trust it not to crack or break lifting 454'seven if you are using them as a 4x8 there is no real good way to make the thing stable at those kind of distances. I would seriously conside going stem to stern with the lifting device to keep the span shorter. No more than 5 or 6 feet thats how I did it and have used the rig numerous times to lift motors. If you are going to use 2x4's to make that kind of span I would suggest nailing or screwing them into an I beam at least. A 6 foot 4x4 can hold the weight of big block motor no problem. But I would be careful about supporting that weight on my side decks as the compression being transferred is considerable you may end up with some cracking or worse on the gelcoat. I used this device as you can see I had all 4x4 construction and a short span with a lot of bracing at 45 degree angles. My flooring in this area is 3/4 inch plywood with lots of support and I made sure the feet of the rig were very close to horizontal and vertical supports from underneath the floor. Good luck with your lift! And I mean that seriously.
Mark Weller
