Budman II

iTrader: (1)

Daniel, what you are describing is the Merc Silent Choice exhaust or the Corsa Captain's Call. Both use a diverter to allow you to direct the exhaust only out the prop or through both the prop and the transom tips. The Merc version uses an air pump and air actuators, and the Corsa uses electric solenoids. I happen to have a set of Gil performance manifolds that came off of a high performance HP500 engine. They have the air actuated diverters built right into the stainless risers. I was going to use them on my boat, but had alignment issues because my boat was originally small block, and the tips were closer together. I may end up selling these down the road.

Otherwise, you may have to ditch the Y-pipe leading to the prop and go thru-transom full time.

daniel475

who our you guys dealing with for all your aftermarket parts??? for building one of these motors ..i live in canada so if anyone knows a dealer around British Columbia it would be great.. the only real reason i wanted to put a supercharger on first and not just build a crazy motor is because I didn't think the hull would handle all the hp .. was thinking a supercharger would push me into the mid 80s and still hopefully be safe !

Budman II

iTrader: (1)

If it has the Manley Inconel valves, which I believe is what merc was putting in them, you may see "Manley" stamped into the stem near the tip. You will have to remove the valves from the heads to see this.

Otherwise, as I stated in my reply to Haxby, it is very tough to tell. You'll know they're NOT inconel when a valve head snaps off and grenades your engine for you. There is no more thorough way to completely destroy and engine.

daniel475

haha oh lets hope that doesn't happen when i do this right lol

articfriends

iTrader: (1)

Keep in mind though, Inconel or not alot of guys have bolted blower kits to gm mag efi motors and not broke/dropped valves, Smitty

HaxbySpeed

Daniel if you really do want to do it right, search some of articfriends earlier posts. There is probably no one on this board with more first hand knowledge about supercharging a mag motor yourself. He also made a 70mph boat run almost 100 and tuned it himself. FogduckerIII has the same platform as you, did most of the work on his own and has his little Scarab running mid 80's. There are lots of examples..

Budman II

iTrader: (1)

Good advice - you will find his epic post about oil coolers, oil lines and bypasses pretty useful and interesting. If you don't already have an oil temp gauge, you will probably want to add one after installing a supercharger. As horsepower levels increase, so does heat, and the oil has a large role in helping the engine get rid of that heat, maybe even more so than the water going through the engine. The stock oil/PS combo coolers that are common on the MAG motors are usually not up to the task of keeping the oil temp below 250* or so where it needs to be. This is especially important on a supercharged application.

daniel475

thanks for all of the advice .. i think i might go without the supercharger route take the motor out this winter freshen it up and build it up for some more hp .. would be more reliable then a supercharger from what I have researched so far.. aswell guys If i were to change my brave one leg what would be out there for a better leg for me? aswell if I do get this motor built it should have around 600 hp if not more .. what would a good prop selection be? I know im gonna be messing with props i just hope i dont have to buy tons of them... and could find someone that would let me try them and if it wasn't working try another one till i found the right one..

thanks
daniel

GPM

Maybe look for a 540 and some headers, leave yours alone for a spare.

Budman II

iTrader: (1)

That or an HP500 takeout. As far as props, you need to get current boat weight, deadrise, speed, RPM. After upgrades, you can figure on going up a few inches in pitch. Might be money well spent to send prop off to be labbed for your application.