B&m 250 or alum heads?
03-03-2013, 10:47 PM
#11
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iTrader: (3)
Last year my father and I built a 509 from a gen 6 block we decided to go with the Dart 308cc Iron Eagle heads, with the SRP mini dome pistons, a quick fuel 950, and the dart single plane intake. We made 601 horsepower on the dyno. It made 601 @ 5600 rpm. The motor went in a 1989 Sea Ray Pachanga 22 and we ran 85.6mph and was not satisfied... so we have replaced the dart single plane intake with a Pro-filer Sniper Jr. Intake and have switched heads to Edelbrock Performer Marine aluminum heads. The motor is going on the dyno this week I hope, but if your interested i'll share the new dyno numbers to give you and idea on what you want to do. If you want to know more deals about my motor since its similar to your feel free to ask.
That's haulin in a 22 pachanga !
03-03-2013, 11:01 PM
#13
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My 27 with a 509,stock 088 heads , Hp500 intake,carb and cam ran 68mph.. (24p Bravo 4 blade)
Same exact engine setup with a Weiand 256 set at 5lbs of boost ran 82mph.. (28p Hydro P5 5 blade)
Blower setup ran me $2000..
No heads in the world are gonna give you 14mph with no other engine changes....
Same exact engine setup with a Weiand 256 set at 5lbs of boost ran 82mph.. (28p Hydro P5 5 blade)
Blower setup ran me $2000..
No heads in the world are gonna give you 14mph with no other engine changes....
Last edited by HTRDLNCN; 03-03-2013 at 11:04 PM.
03-03-2013, 11:48 PM
#14
my 27 with a 509,stock 088 heads , hp500 intake,carb and cam ran 68mph.. (24p bravo 4 blade)
same exact engine setup with a weiand 256 set at 5lbs of boost ran 82mph.. (28p hydro p5 5 blade)
blower setup ran me $2000..
No heads in the world are gonna give you 14mph with no other engine changes....
same exact engine setup with a weiand 256 set at 5lbs of boost ran 82mph.. (28p hydro p5 5 blade)
blower setup ran me $2000..
No heads in the world are gonna give you 14mph with no other engine changes....
03-04-2013, 07:23 AM
#16
I also have a friend that has a 28 velocity with a similar setup, his boat is for sale at http://www.powerboatlistings.com/view/20204 . I will be sure to relay the new dyno numbers, hopefully there will be some kind of an increase, if anything the aluminum heads are lighter...
03-04-2013, 08:07 AM
#17
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iTrader: (4)
Ive been running various blowers for about 6 seasons now. I haven't had one issue blower related. The engines, start great, idle great, power is awesome.
Reason people are leary of blowers is because they always heard thru a friend about meltdowns. The 100% most important thing with any supercharger, is the tune. If the tune is off, yes, it will destroy parts.
As for your 850 carb, it will be enough if you purchase one more to put next to it. 700HP is a stretch with a single 850 on top of a roots.
Heres a link to my budget builds. 800HP 468's.
http://www.offshoreonly.com/forums/d...oed-today.html
Reason people are leary of blowers is because they always heard thru a friend about meltdowns. The 100% most important thing with any supercharger, is the tune. If the tune is off, yes, it will destroy parts.
As for your 850 carb, it will be enough if you purchase one more to put next to it. 700HP is a stretch with a single 850 on top of a roots.
Heres a link to my budget builds. 800HP 468's.
http://www.offshoreonly.com/forums/d...oed-today.html
You also only hear the bad, not the good of guys out there running all the time with no problems.
Platinum Member
03-05-2013, 06:36 AM
#20
CP, my buddy Tim (posts on here as "BadDog") was running a 250 and a big, non-dominator Holley on his 509 a few summers ago. He was gettin low 80's in a Baja Force 235. He sent the carb out to Dean Nickerson for tune and setup, and bought a custom roller cam from him that was designed for the blower. The rest of the engine was pretty much stock 502 like yours - stock unported 088 heads, Lightning headers, etc. He went through a couple of iterations with that build - first he hammered a rod bearing out of it, and later he broke a connecting rod and sent it through the pan. He did put a lot of hours on both motors between builds with hardly any problems. This last time he decided he was done with the blower and built an HP 500 clone out of it. He is running about 72 GPS with it now. He will be the first to tell you that he misses the punch that the blower provides, but if you want to play, be prepared to play. Basically, you can claim all you want that you will run go easy on it, mostly cruising, blah blah blah, but as Tim famously put it, "if you had a 12-inch schlong, would you only use 6 inches of it?" 
Tough choice, but you also have to consider things like hatch clearance, how much room there is in front for pulley clearance, etc. What kind of water are you running in down there where you boat? Fresh, or salt / brackish?
BTW - did you get that link for the Cometic gaskets?
Tough choice, but you also have to consider things like hatch clearance, how much room there is in front for pulley clearance, etc. What kind of water are you running in down there where you boat? Fresh, or salt / brackish?
BTW - did you get that link for the Cometic gaskets?
