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Cost of 454 to 540 upgrade?

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Old 02-01-2008, 01:51 PM
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Originally Posted by waterboy222
So there is really NOTHING I can do to these motors to bump the horsepower? Maybe Ill just spend the money on rebuilding the motors and dressing them up a little and be happy with my 70mph and reliability.
I have the same engine you do. I did a budget upgrade due to a cracked head, details in this thread - http://www.offshoreonly.com/forums/s...d.php?t=178200

If your engines are in good running condition, then the plan someone else above suggest might be best - sell them outright and build up a set of 467 or 496's from scratch using good but budget minded parts.

If you are set on using your 330's, there are options but not with a lot of bang for the buck. Probably for your application it would be new pistons, new heads (049's or 781's or somethink like Edelbrock aluminum oval ports), bigger cam and new exhaust and intake manifolds. But like others have said above, at that point you've tossed out most everything on your engine so you might as well start from scratch.

So, sell the 330's and build up some nice 496's would be my suggestion. Bounus points if these 496's had aluminum heads (Edelbrock?), aluminum intake (Performer RPM?) and aluminum exhaust manifolds (496HO take offs?) then you would have one helluva weight savings (500lbs for 2 engines???) vs what you have now!

Last edited by ECeptor; 02-01-2008 at 01:55 PM.
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Old 02-01-2008, 01:52 PM
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Originally Posted by Chris Sunkin
The reality is you might be able to get 30-40 horsepower with the heads and exhaust you have now. You'd have to replace the cam, manifold & carb. Power comes from increases in displacement, RPM, compression and cam timing- usually at least two or three are required to have some effect. Then you need related componentry on the intake/exhaust
to make it happen.

If you really like the boat, I'd say go for it. You have to stop looking at what it's worth and what you'll be spending. You do need to consider all the expenditures though. There's no sense in getting halfway thru and discovering you can't afford to finish it. At least it runs now.
Ok so say im able to get another 40 hp out of each motor. Now im at 370 hp. Am i going to see any difference in speed with that small of a hp increase?
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Old 02-01-2008, 02:13 PM
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Originally Posted by waterboy222
Ok so say im able to get another 40 hp out of each motor. Now im at 370 hp. Am i going to see any difference in speed with that small of a hp increase?
Using this site - http://www.go-fast.com/boat_speed_predictions.htm

If I assume 7000lbs, 620hp at the props, 70mph that gives a hull constant of 235.

Keeping all things equal and adding 80hp nets you 4mph. That might be optimistic.

Going to 2 x 500hp (470hp at the prop) 496's nets you 86mph. Again, sounds optimistic to me, but you get the idea.
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Old 02-01-2008, 02:19 PM
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500 hp and 86mph seems ultra optimistic to me. I think at one time they produced an SS version of this same exact hull and they were equipped with B1's and hp500 merc's and were running 79 and 80mph.
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Old 02-01-2008, 02:20 PM
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Originally Posted by waterboy222
Ok so say im able to get another 40 hp out of each motor. Now im at 370 hp. Am i going to see any difference in speed with that small of a hp increase?
1-2 mph on top. A little more pull getting there.

A good builder could probably assemble a pair of 468's for you for under $3000 each. Iron head, hydraulic roller, holley 800, msd ignition, etc. You'd see 475 hp or so. That wouldn't kill your drives. That should give you 10+ mph and they'd be 500+ hour motors. You'd need exhaust and external steering though. That might make more sense.
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Old 02-01-2008, 02:23 PM
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Originally Posted by waterboy222
500 hp and 86mph seems ultra optimistic to me. I think at one time they produced an SS version of this same exact hull and they were equipped with B1's and hp500 merc's and were running 79 and 80mph.

There you go. Hard data points are always better than a calculation. But, that calculator is the only one I've seen online.
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Old 02-01-2008, 02:24 PM
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Originally Posted by Chris Sunkin
1-2 mph on top. A little more pull getting there.

A good builder could probably assemble a pair of 468's for you for under $3000 each. Iron head, hydraulic roller, holley 800, msd ignition, etc. You'd see 475 hp or so. That wouldn't kill your drives. That should give you 10+ mph and they'd be 500+ hour motors. You'd need exhaust and external steering though. That might make more sense.
What are his stock 330's worth if he sold them?
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Old 02-01-2008, 02:24 PM
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Originally Posted by Chris Sunkin
1-2 mph on top. A little more pull getting there.

A good builder could probably assemble a pair of 468's for you for under $3000 each. Iron head, hydraulic roller, holley 800, msd ignition, etc. You'd see 475 hp or so. That wouldn't kill your drives. That should give you 10+ mph and they'd be 500+ hour motors. You'd need exhaust and external steering though. That might make more sense.
thats about what i was looking for.. roughly 500 hp. $3k would buy a complete motor or would i need to give them my blocks or purchase seperate blocks?
I could swing $3k for an engine that will produce 475hp
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Old 02-01-2008, 02:39 PM
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Originally Posted by waterboy222
thats about what i was looking for.. roughly 500 hp. $3k would buy a complete motor or would i need to give them my blocks or purchase seperate blocks?
I could swing $3k for an engine that will produce 475hp
You can find good 4-bolt blocks, cranks & heads pretty easily. You might even consider a SCAT motor kit. For about $1600 you get rings, bearings pistons, rods and a stroker crank. Find a nice block for $350 and a set of good heads will probably set you back $750 with stainless valves. Ad a cam/lifters & you're ready to go. Will push the budget a bit but now your over 500 horse at 496 cid.

The Merc 330's should bring a decent buck, offsetting your cost- or paying for that external steering.
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Old 02-01-2008, 02:44 PM
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Originally Posted by James
Scott is a good guy - the internet and national dragster and PB are great places to advertize and I'm thrilled to hear that Scott has built solid product - but as you guys have expereinced - organization and cleanliness is not his specialty. But Scott alone helps to keep other supplier cheap - for that he is good -
Right On JAMES !!!! you get alot of motor/hp for the $$$$ and he can build it cheaper then i can piece it together and dyno it here
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