I wanted to try something that I haven't seen done before and it's working well. With the exception of some 2" Square Tube and Plate Steel up front, the entire Dolly is constructed from Pine 2x4's and 2x6's and held together almost entirely with 3" Deck Screws.
The Tube Steel in front was necessary for two reasons: wood would not be strong enough and the Dolly will later be used to Cradle the Engine and Transmission for testing prior to installing it into the Engine Bay. The Engine Brackets will bolt nicely to the Tube Steel and the back of the Dolly will be brought forward and some additional structure added to hold the Transmission Tail Housing. Then when I'm done, I can disassemble the whole thing.
Two other advantages I quickly discovered were that, wood is easier to cut and fix if you're off a bit and it's a whole lot cheaper. The total bill for all the materials, Steel and Wheels included, came to just $137.00. The only change I plan to make is the Rear Wheels. Straight Wheels are easier to control but far more difficult to maneuver than he Swivel's.
By-the-way, I'll assume that y'all will have a good laugh and think I'm nuts, but just in case, please do not copy what I built unless you're extremely comfortable working with wood and understand all the engineering.
Ray