super charging 350 mag

[jsm1]

I have a 94' scarab 350 mag. Alpha 1 outdrive. I am thinking about putting a blower on it and i am curious of what these outdrives are rated at. Also any advice from someone who has put a supercharger on theirs.

 

[FunInDuhSun]

Re: super charging 350 mag

Alphas are rated to 300HP.
They can survive for awhile with more if not abused, but consider it a timebomb.

 

[jsm1]

Re: super charging 350 mag

So whats the best way to fix this weak link? Can they be beefed up? or do i need another outdrive. Is it possible to put a bravo 3 ? Thanks

 

[lilb]

Re: super charging 350 mag

If alphas are only rated for 300 hp then why did they put them behind big blocks with 330hp and alot more torque than the 350? But that doesnt mean it will hold up to a blown 350 though. You could witch to a bravo but you would have to change every thing from the motor back.

 

[jtmarten]

Re: super charging 350 mag

I have a 94' scarab 350 mag. Alpha 1 outdrive. I am thinking about putting a blower on it and i am curious of what these outdrives are rated at. Also any advice from someone who has put a supercharger on theirs.

A question better posed on offshoreonly or speedwake. Lots of guys running up to 400hp on alphas, you just have to be easy on the holeshot. Good thing is, the small block won't have the torque to tear up the drive like a big block does.

 

[carcraze]

Re: super charging 350 mag

They did put a 454 on the alpha for, I believe, 2 years. I would assume the very short peiod of time would indicate they had some issue with them. I have heard of alpha's holding up with over 300 but they are driven with caution. The best would be going to bravo but it is a large change as far as I know.

 

[jtmarten]

Re: super charging 350 mag

If alphas are only rated for 300 hp then why did they put them behind big blocks with 330hp and alot more torque than the 350? But that doesnt mean it will hold up to a blown 350 though. You could witch to a bravo but you would have to change every thing from the motor back.

$$$ savings. They learned quickly though, I think '87 was the only year for BB/Alpha setups.

 

[zbnutcase]

Re: super charging 350 mag

If alphas are only rated for 300 hp then why did they put them behind big blocks with 330hp and alot more torque than the 350? But that doesnt mean it will hold up to a blown 350 though. You could witch to a bravo but you would have to change every thing from the motor back.

Basically a stopgap measure until the Bravo came out. And Alphas can break with a lot LESS than 300hp!

 

[Don S]

Re: super charging 350 mag

86 to 88 was the 454/Alpha time span. In 88 The Bravo drive came out.

The outdrives would hold up, as long as you didn't let your throttle hand get carried away. We all know that people with Scarabs never race their boat, in any way.

 

[jsm1]

Re: super charging 350 mag

any other ideas to gain 7-9 mph. I currently can hit 63.3 or so on gps and need 70 or 71 to outrun my dad in his baja (24' 502). Im running a 21 pitch prop. Engine has cam, heads and intake ported and polished and exhaust matched. Any ideas would be appreciated.

 

[69rrvert]

Re: super charging 350 mag

any other ideas to gain 7-9 mph. I currently can hit 63.3 or so on gps and need 70 or 71 to outrun my dad in his baja (24' 502).

Is it really worth the $$$ and possible carnage just to outrun dear ole dad? Thanks, Steven

 

[jtmarten]

Re: super charging 350 mag

any other ideas to gain 7-9 mph. I currently can hit 63.3 or so on gps and need 70 or 71 to outrun my dad in his baja (24' 502). Im running a 21 pitch prop. Engine has cam, heads and intake ported and polished and exhaust matched. Any ideas would be appreciated.

Drop in a 502/Bravo setup.
What is your compression ratio? Low enough to run FI? Heads P&P on just exhaust, or both? Can the exhaust system handle the extra flow efficiently?
What is your WOT rpm with the 21?

 

[jsm1]

Re: super charging 350 mag

the 502/bravo setup would be nice. . The compression ration is still whatever the 94 factory 350 mag had? im guessing 9.5 or 10 to 1. I think with no more then 5-6 pounds of boost it would be ok. my rpms are about 5400 at WOT. I don't know the range on this cam yet, im working on getting the cam card. The head work was on intake and exhaust ports and the intake was matched to the heads. All done on a flow bench, and roller rockers added. I just put a 750 double pumper on.

 

[jtmarten]

Re: super charging 350 mag

You could bump up the prop pitch for sure, two, maybe three inches. That'll net you several mph.

 

[wca_tim]

Re: super charging 350 mag

Make sure you're propped for your wot at peak horsepower rpm

make sure your running surface is clean and straight (worth more than many people realize)

engine mods are not trivial if you want to pick up a lot of speed...

weight, especially in the *** end is important. every hundred pounds makes a difference

the lighter the boat and the throttle hand, the longer a well-maintained alpha drive will last behind more horsepower. I'm currently around 450 or so, but in a light boat. I know a guy with more like 550 or 600 that has had years of decent service from a stock alpha drive. maintain it well and realize that it's a wear item.

speed in a boat takes real horsepower, and costs money. period.

in my experience...