Thread:

Your opinion

If it were Me, I would build all that 509 stuff you have up, sell the 496 for some $$ and make a runner out of it. You may consider installing EFI on it so it is easy to manage cold and around the docks. After reading, you may even enjoy the project. Anyway-enjoy!

Hello There! It sounds like the motor parts in your garage may be a fun time to finalize and install into your boat. If it were me, I would sell the 496 Merc Engine as they have a decent resale value now that they are un-available. Maybe take some of those funds and finish up your 509. It sounds like you on the right path with parts and with a few months of gathering--you can finish it up. With the specs quoted above, your camshaft choice will be very important as to the outcome of the final horsepower and torque. We have specialty grinds made for us my various venders that may help go get there. At the end of the day, I am sure you will be in the 80's with a mild built 509 if you X-dimension and set up is correct. As for the drive, I would normally say a minimum of XR, however we have several clients who have 600+ hp with X drives as well with no current issues. Feel free to contact me if you need any assistance and we can discuss it. Have a great day!

Originally Posted by freakdave

First of all, thanks for replying to my message. I have a 2006 Advantage 28 sport cat open bow. Love the boat but....496HO is not going to cut it in the near future. Want more just like anyone else and also on a budget, go figure. I am not looking at getting 100 mph but would like to hit the upper 70's low 80's top end and be able to cruise in the 60's without winding the motor up for great lengths. I have a brand new Dart Big M 509 short block with 4340 Eagle/SRP internals Clevite H bearings in my garage. Would you A.) supe up the 496 or B.) complete the engine that i have in the garage? I have a Victor Jr intake and Demon 850 plus a Milodon pan, Hayes flywheel, Summit balancer, Teague crossover with bypass, MSD billet distributor, and some nuts and bolts. Dont have any of the accessories, camshaft, lifters, pushrods, ignition, or pulleys or belts.Would it be it my best interest to consider selling the engine project and getting a supercharger for the 496 or complete the 509 engine project in time? I have a Bravo X outdrive with a Bravo 1 22P prop. What horsepower and torque with pump gas can i achieve this 80+ mph boat ? I am looking for increased mid range punch and overall top performance but my driving habits are mostly cruising with bouts of high end running. My 509 short block is brand new and has the SRP low dome profile pistons #212140 17cc .020 in the hole and i am guessing 9.5 Cr with Childs and Albert Zero Gap Seal rings. If i go the 509 route i would consider using AFR 305 heads with a custom ground camshaft probably from Bob Madera of Marine Kinetics. I I am not in a hurry at all. In fact i thought about getting a labbed 24 prop and seeing how it does with the current set up and maybe some aftermarket Dana Exhaust but i have heard that aftermarket exhaust on a 496 HO with such a big boat doesnt justify the cost. What direction do you think i should take? I want realiablility, and moderate performace. Either way it will be a long term project. thanks for your time, Dave.
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wheres dyno man