I think 50 dollars and hour is pretty accurate, 50 gallons an hour no way. Small blocks are way better on gas but 29ft is also pretty heavy for small blocks.

yeah I was way off on my figure for gallons per hour I checked my friends fountain smart craft on his boat and at 3500 he is only burning 15 gallons an hour and it has twin 496 mag ho's so I should be a bit less than that so I help this helps

My boat burns about 20 GPH at cruise( 40 mph) and around 50 at WOT ( 66mph) . 29 Scarab should be the same or less. I have twin 6.2's and above figures are for both motors- total fuel burn.