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Ryan00TJ - thanks - thinking I might just have to put this one together with what I've got, clearance it to what the recommendations are and run it... I'll check on the XM270 - I'd like to run thru-hull exhaust except the transom doesn't have a nice flat spot that's a straight shot out - going to have to do a little curve to get out and wondering if it's worth the cost...
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We used Stainless Marine and Bullet Racing Cams in our 383's . The cam was 223/[email protected] 530/548 HYD Roller made 425 on the dyno .:D
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Originally Posted by formula 382 sr-1
(Post 2362243)
We used Stainless Marine and Bullet Racing Cams in our 383's . The cam was 223/[email protected] 530/548 HYD Roller made 425 on the dyno .:D
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The pix. picked up 4.7 mph on GPS when we changed out the cam . The old cam was from Crane 222/222 @ .050 .467/.467
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Originally Posted by bwiencek
(Post 2362251)
What's the rest of the combo (heads, compression, etc.)
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Hi all,
I'm in pretty much the same boat. I'm considering 383's for my Scarab. I have the silent choice option on my boat, can I block that off or remove it completely? Don't get me wrong I love features, but I'll probably never be in a situation were I would need a system like that. Ok, let's change gears and ask if I decide to run the 383's with the silent choice engaged, will that put more strain on internal components due to the resistance the water will have on exhaust? All comments are welcome. I even accept constructive criticizum<-- probably spelled wrong...I know...LOL. |
You can run it with 383's it will only keep to a smaller cam shaft because of reversion. They do make a blockoff plate for the y pipe. It all depends on what you want.:cool-smiley-011:
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Originally Posted by formula 382 sr-1
(Post 2362260)
Scat crank Scat rods World Sportsman II 72 cc 200 cc runners -12.0cc dish pistons 9.3 compression Edelbrock RPM Intake carb was Edelbrock 750cfm marine 425 @ 5450 RPM.
What type/brand of piston did you use? Are you getting any detonation with the compression you're running? Mine should be real close as I've got -18cc pistons and 64cc heads (82cc vs 84cc volume in the chamber+piston) I've been looking over cams and was wondering if anyone had any thoughts on running the Nitrous HP cams - NX276HR specificially - it's got a long exhuast duration which I would think would help with a restrictive exhaust setup, and a wide lobe center that should help with reversion.... SPECS:: Basic Operating RPM Range: 2,000-6,000 Duration at 050 inch Lift: 224 int./236 exh. Advertised Duration: 276 int./288 exh. Intake Valve Lift with Factory Rocker Arm Ratio: 0.502 in. Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.520 in. Lobe Separation (degrees): 113 |
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400 small blocks.dart 200 heads, cast crank, fluid damper balancer, good exhaust,480-480, 230 230 108-110 cam 420hp. they ran great and were super reliable. (The race pics is from the new owner).sbc are great motors when done right.mine were built with help from speed service ,chicago.
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Flywheel: An externally ballance auto flywheel will work fine. You'll just need a coupler (bravo/alpha) or drive plate (transmission).
As for buying the new merc 383. Check ebay. I've found new bobtail motors for between $6-7K. Not sure about long blocks. But I did notice that the Merc 383 came out at the same time that GM started offering their crate 383 truck motor. Hmmmmmm? Gary
Originally Posted by bwiencek
(Post 2352476)
Of course there's a budget - it's whatever the "boss" says I can spend :D If I don't buy the lighter exhaust setup that will free up some cash. I'd do the roller cam if it was a late model block that was already set up for it. I've got a line on a good '98 vortec pickup engine that is supposed to be a 4-bolt main and I can pick up and it's already fitted for stock hydraulic roller stuff - I'd just have to get it built with other internal components...
If I've got to go steel crank and forged pistons I might as well build something else... When yoy say "Pin them too" - are you referring to rocker studs?? (the heads already have screw in studs with guideplates) I guess I should say that I'm not looking for huge HP - 325hp would probably be fine which is 25% more or so above the stock mercruiser engine - something a little stronger than a stock but don't want to put a $10k engine into it. How much are those 377/383's? Can they be had in a long-block form? |
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