580 cid Donovans in my cig. Lost one after I bought it and could only save the block, 5 sleeves and heads. Pulled both and had Dave Wesseldyk build it and tune both up on his Dyno. When I bought the boat it was being run on race gas and all he did was take the 120 jets out of the carbs and wound up with around 98's and pump gas. Same pullies and very reliable ever since.