Engine for new boat, questions

[Kachina26]

So, if one was to build a new boat, and wanted to go with something a little more exotic than the Merc lineup, what would those of you in the know recommend? The boat would be 27-29 feet, and a vee bottom, power would most likely be less than 800 horse, probably even along the lines of 600 horse. What might one expect to pay? What kind of a credit do the builders issue when deleting stock 496mag power?
Sorry for the double post, I put this in the sandbar as well for more visibility, but I know some of you folks don't care for the drama over there, and I wanted your opinion also.

[steelcomp]

I think the first step is trying to pin down what it is that you're looking for specifically. What kind of speed, what type of use you want out of your boat, rpm range, budget, that kind of thing. There's a big difference between 600 and 800hp, in both performance and expense. Then it seems your best bet after that would be to find a reputable engine builder who understands your combination (hull, drive, type of use, etc) and what your goals are, and can give you the best value and performance for your dollar. It really boils down to what you want, and are willing to spend.

[obnoxious001]

Yep,, what Steelcomp said. 600 hp in a single engine v bottom boat that large won't be real fast. Over 600 hp, and you have to consider what you will do to the drive to make it live. When you said "exotic", what did you mean. 600 hp should be fairly easy from a decent combination of parts and around 500 cu in, pump gas engine.
I just finished this one for a board member, well under $10k even once it gets valve covers and carb. Block, pan and intake were used, everything else new, forged internals. Of course, you still need all the accessories to bolt on as well.
http://www2.***boat.com/image_center.../1132496-2.jpg

[victorfb]

looks nice obnoxious001. is that a tall deck?

[Kachina26]

Yep,, what Steelcomp said. 600 hp in a single engine v bottom boat that large won't be real fast. Over 600 hp, and you have to consider what you will do to the drive to make it live. When you said "exotic", what did you mean. 600 hp should be fairly easy from a decent combination of parts and around 500 cu in, pump gas engine.
I just finished this one for a board member, well under $10k even once it gets valve covers and carb. Block, pan and intake were used, everything else new, forged internals. Of course, you still need all the accessories to bolt on as well.
How do you define "real fast"? The boat I'm looking at runs 80-83 with a merc 525 which is 500 HP I think. I want to be able to cruise around 60is at low rpms, and have a top end just over 80 with a full load. I realize that in some circles that isn't fast, but I would be happy with it. I don't want to go too extreme because I know that with mega horses comes mega repairs. I want to stay in the realm of "turn key" operation. I guess exotic wasn't the right word, I just meant a little more hp than what merc offers for the money.

[obnoxious001]

looks nice obnoxious001. is that a tall deck?
Thanks, yes it is, I like the rod geometry you can get with the tall deck blocks and longer rods. This one is 496 (4.310 bore x 4.250 stroke) with 6.535" rods.

[obnoxious001]

How do you define "real fast"? The boat I'm looking at runs 80-83 with a merc 525 which is 500 HP I think. I want to be able to cruise around 60is at low rpms, and have a top end just over 80 with a full load. I realize that in some circles that isn't fast, but I would be happy with it. I don't want to go too extreme because I know that with mega horses comes mega repairs. I want to stay in the realm of "turn key" operation. I guess exotic wasn't the right word, I just meant a little more hp than what merc offers for the money.
I did a 588 cu in, single Dominator carb engine for a neighbor last year, for a 29' Scarab. We took it to Elsinore with nothing to test speed, and apparently he thought it was going to be a rocket ship compared to the 540 that he had blown up in the boat. I thought it was pretty respectable for pushing a big lump through the water, and I used to race a turbo charged Schiada, so everyone's concept of speed is different. The 588 was a brand new shortblock, using his Brodix heads rebuilt off his broken engine, and we came up around $10k, for what might be about 725-750 hp.

[TIMINATOR]

For what you want, you COULD use an old tall deck and rebuild it, but if you start with an aftermarket block you don't have to spend the $$$ clearancing the crankcase, magnafluxing, bake,blast-cleaning it, and buying it in the first place. Besides the block will be 20-30 years old. The stroker cranks/pistons are essentially the same price for any stroke, so why limit yourself with somthing that can only be 496/510? When you can build a 525,540,565,572 for almost the same price, why stay small? The bigger engine has more vacuum and will get better fuel economy than the smaller engine, unless you are really stomping it! But then it is still faster than the small one anyway. It is just my opinion, but thats the way we do it here. We have NEVER had ANYONE come back in and say they wished they built a SMALLER engine, NOT ONCE!!!!!!!! TIMINATOR at TUF-ENUF AUTO & MARINE PERFORMANCE 623-877-8553 :hammerhea

[obnoxious001]

Good point on using the new block,, which is what I did with the 588. It was a new Dart tall deck, since the guy's old 540 had sleeves and damage from a broken rod. I normally offer the same advice, cubic inches don't really cost much different, and do offer more horsepower and torque.
The 496 with the used block saved the guy about $1700, no grinding for clearance was required, and this particular block was a nice piece, not one that had been rebuilt a bunch of times. I mentioned that engine was under $10k,, I just didn't say how far. My customer knows he scored a deal on that one, I will leave it at that. With a stock Bravo drive in a 21 foot boat, this little 496 should be pretty nice.