Cost of 454 to 540 upgrade?
 

I have the 330 hp 454's with Bravo 1's and no hydraulic steering. Im considering a complete repower this spring and im not really sure how to go about it.

I think the boat has reached its lowest value that its going to be able to get even with a big repower so sticking with Mercruiser just for resale isnt going to help me any. (in my opinion)

Ive found a couple of places online that I can purchase a base 540 bulldog/attackdog type engine for around $8500.

What other expenses should I add on top of this? Will any of the parts from my 454's work to dress out the 540's or will i need to buy all new stuff?

Can someone give me a quick estimate or rundown of what its going to cost to do an upgrade like this or should I just have my motors rebuilt and upgraded for more HP..

Im running abt 70 right now and would like to run 85-90 but dont want to have to change drives because they were just rebuilt. I know ill need to get hydraulic steering for those speeds and torque.

Any advice? its for my 32 Sunsation Dominator.

Punt :D

That sounds like the price from 1 800 runaway, I mean runsnew. Do a search on OSO for them and get the whole story. I seems their engines can be good, but if you need the warrente they are worthless.

One, of many, other things is your motor mounts. I would think you would want offshore style mounts rather than the stock Bravo mounts, if you don't have them.

Nothing in the 330 is usable for what you want to do. They're pretty much low-po motors and won't take kindly to performance mods.

$8500 sounds about right for low-end 540's but you're going to have to add in better coolers, all-new exhaust, solid mounts if you don't have them already, carbs, ignitions, etc. And a new fuel system. With hydraulic steering you're probably looking at $30 grand. Do you want to put that much into the boat? Maybe it's worth a look at what your boat and $30K will get you in another boat.

540's are also going to be hard on those Bravo's.

Waterboy get ahold of jeff1000man he'll set you up and probably got one laying around ... we are just finishing one now and with a 4 bolt, rotating assembly from Dynaflo , a good set of heads & the blower off OSO classafieds were at 5800.00 to date and only thing left is the nickerson carb and fill it with oil ... that 540 will smoke thru drives but pickup some spares for 1000.00 apiece and keep one in the pickup and run the chit out of it

You might consider just stroking those to 496's, following this combo and et around 640hp.

http://forums.boatfreaks.org/showthr...&highlight=496

Small oval heads and 2-bolt mains on those 330's would be a barrier.

Either set actually right now.

http://www.offshoreonlyclassifieds.c...o21049-en.html

http://www.offshoreonlyclassifieds.c...o20829-en.html

I can leave the blower out of the equation on the 540's.

You could send me you 330's and get them upgaded also if you want.

Either set of engines is going to get that boat in the high 80's low 90's

We have one of those boats down here right now with 600 HP a side and it runs in the mid 90's.

You can have the two bolt made into four bolt.

Technicaly yes, you add the 4 bolt caps and have the machine shop drill them in and you have a 4 bolt.

I actually don't do that though. I just use the 2 bolts for other projects, and sell the 4 bolt blocks as part of the deal.

I sort of have an iron collection down here.:cool-smiley-011:

I see the name Dynoflo came up - I love there adds - I love the prices even better - I have been tempted - I have visted the Dynoflo shop near Vegas on (2) occasions - I like the owner -the warehouse is in a good area - the warehouse is nice - all good news so far - I have been known to date fat chics, I'm not that picky, and even more important I'm cheap -

I would NOT PURCHASE an "assemble part" from Dynoflo - Assebly needs to take place in a clean, quite controlled environment - that is NOT Dynoflo

I get mixed results from them, and have purchased quite a bit of stuff from them in the past. Scott is a very reasonable man to work with and his staff are very friendly on the phone. I do get the feeling that they are getting to much business to handle though. The last couple orders have been screwed up and have cost a lot of down time.

THere are a lot of other suppliers now that are competitive with their pricing. I will probably still use them from time to time though.

I'd argue with you on that one , i had 2 1050 hp blower motors built by Scott complete pan to carb and he did what he said, we beat the livin chit out of them and its been 3 years and there still out there runnin awesome and we just do 10 hour old changes ...
i will also agree with JEFF they have gotten a lil to BIG and with the counter help things are'nt as flawless as when scott did it . i just sent back 2 cranks they they shipped wrong , and a set of pistons but they made it all right just set the job back 2 weeks cause they refused to send the right cranks till they recieved the wrong ones back and i even ate the friggin freight ... :cool-smiley-011:

He sent me 2 sets of rod bearings for SBC. I didn't catch it because I was used to having Scott get everything right and sent the stuff directly to the machine shop. The guy called on the phone and said WTF is this?

You have to take the good with the bad. :Whatever:

maybe you we're at a diff shop , the place we were at was DYNA FLO in Kingman Nev

Ditto , he did the exact same thing and sent me the cheap bearings ,we tossed em in the garbage and bought a set from Winners circle the clearances were so off ...... Im sorry to say i think Scott advertized in powerboat with some great prices and got so buzy he dont give a crap anymore ...The last phone call he was so put out by a problem with his guy sending a gen 4 crank for a gen 6 and hung up the phone and said he was too busy to talk i almost sent it all back and cancelled it on the credit card ... he built 2 good motors that he insisted i could run to 6600 rpm and they would'nt break and we did'nt and i tried my damdest ..even had a spare motor on the shop floor cause i thought i could break em ...

And you'll still have the thin-web passenger car block and twice the expense. 4-bolt blocks are plentiful. In addition, complete Mercruiser engines are valuable. The heads and cranks individually are almost worthless. Complete it will bring enough $$ in rebuildable condition to get you a 4-bolt block and probably a nice set of rectangular heads. In there you can stick a 4.25 stroke SCAT rotating assembly and have a 496 for about $2500.

That is why I don't actually do it. :D

BOY let me know if your needin some good rec port heads , got a good guy in LOTO pallets of them with good 225 Int and 188 exh Inconel and dirt cheap .good luck

LMAO :D:cool-smiley-011::cool-smiley-027:

There's one avenue that seems all but forgotten... the 427 truck block. It's a tall deck but it's also super-heavy. The bores aren't siamesed but they're really thick and the webs too. I've yet to see one that won't take a .100 overbore. Last one's I bought were $300 each on racingjunk.com

I have one of those blocks. Havn't been able to come up with a good solution to build anything worthwhile out of it.

From what I have read, you can't get a big enough bore to make it worth the effort..

You can stud a 2 bolt block and it will take a 550 HP engine. A 4 bolt would be better, but you gotta use those 2 bolts some times.

They're way thicker that HP blocks. Send it out and have it sonic measured. I've yet to see one that won't take a .100 overbore.

The 2-bolts are fine for mild street motors. Most of those guys spend seconds at max RPM and most don't free rev them and drop the clutch repeatedly.

So what would the bore size be. I thought they were 4.25 blocks.

What could you make with it?

Oh, and I thought 550 Horses was mild motor?:D Studded 2 bolt blocks hold up pretty good with the 4" stroke, NA applications. I don't use them for anything longer stroke or with a blower set up.

By the way, thanks for the hook up on the dealer info. :D

THose blocks were built taller so that they could put the taller piston with the extra ring on it to run at high rpms for hundreds of thousands of miles.

who has the pallet loads of heads here at loto?

They are. You can go 4.350 and 4.250 stroke with no interference. Gives you a beer-budget 505 and better torque than a 502. Grind a little on the pan rails and the liner bottoms and you'll fit a 4.375 or even a 4.5 crank in there. That gives you 520 or 535. Lov-rev/big torque.

The only advantage you gain with the larger bore on the 502-up is the unshrouding of the intake valve but that's negligible. You trade 10 peak horsepower for 25 ft/lbs torque across the board with the 505.

starting to think all this is just way above my head.. I absolutely love my boat so I dont want to sell it and try to find something that will run 90 just to get that speed. Plus I could get about $33k for my boat (if i sat on it for 2 years with a for sale sign cause of this stupid market).By the time i found something that has what I wanted and for that price, itd still be a fixer upper i think..

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.

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.

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 -

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!

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.

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.

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.

There you go. Hard data points are always better than a calculation. But, that calculator is the only one I've seen online.

What are his stock 330's worth if he sold them?

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.

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