Thanks, guys, for the info. I'll let you know what I decide, with scary pictures if it comes to that.
Doc
Doc,
You can use a rafter, most rafters are 2x8's(I'm a contractor & have designed & built many structures) The key question is the SPAN of the rafter...Heres a caculator that will help
http://www.decks.com/Calculators/JoistSpan.aspx
All you need to do is double up the rafter you plan to use... you only need to double up the width of the car & make sure the the 4x4's are placed under the doubled up rafter..Then use 2 lag bolts every 12 inches....Then get 2-4x4's ..2-cap baseshttp://www.strongtie.com/products/connectors/BC.asp#gallery
Run the 4x4's on each side of the car from the floor up to the rafter & screw to the rafter with deck screws. You will have no problem hanging that motor since all the weight will now be transfered to the 4x4's and floor.
Scott