1999 Sport Nautique re-power. ZR409 VS H6.

If I were on the fence if 409 vs H6 I think this would make my mind up: on Miami Nautiques website they sell packaged annual maintenance kits. Annual. As in every year!
Carb’d 351-$143
409 kit-$445
H6 kit- $711

Shoooottt, I doubt I spend $711 in annual maintenance and repairs for my 3 boats put together.

DHMcFadin wrote: This is a long shot but the Python 496 never comes up for sale does it?

I've seen 1 for sale as a pull out since they were new.... The 496 and 502 are however built in marine applications by others. Heck the Mercruiser 502Mag is almost identical to the PCM502 in my boat. I've actually got parts on mine from mercruiser and my oil filter relocation kit is off a buddy's giant blower motor. Just have to be creative since PCM won't tell you a dang thing.

Other random thoughts:

-I'm in the buy a 409 w/trans and enjoy it camp. Still far less than a new boat and can build to suit.

-A stroker GT-40 sounds fun and probably would be. But, in the end that could be a fairly expensive motor and tunning could prove less than easy.

Since these engines are very long life are there any Salvaged boats parting out where you could pick up a complete power train with all necesary connections still attached?
A used engine with less than 500 hours in good shape maybe?

I have been researching having an engine engine built but I have no idea who I would choose for an engine builder who would also supply all the fuel injection components and send it ready to run and tuned. I want the boat to still run reliably, smooth, have multiport fuel injection, etc.

63 Skier wrote: Don't worry about any flack, I think the "keep it original" crowd stop caring around 1995 or so! I can put 4 people in the boat and pull a slalom skier, granted the wake isn't great with all that weight but we do it routinely. I can ballast up and pull a wakeboarder with no issues, I don't think it would matter how many people in the boat. And to bomb around the lake I find my boat a blast to drive and no amount of people challenges the engine. I only say all this because now we know you aren't looking for this to be your primary slalom boat. Why not, as someone above mentioned, repower with a custom built stroker that could use your same tranny and mounts, develop the same power as the 409, and probably sound much better? Granted maybe not the turn the key and go aspect of injection but talk about the cool factor! Anyway I totally understand if you go 409 package instead, just thinking aloud.

I've spent quite a bit of time driving both engines in the last two years. Our re-powered 409 Ski Nautique and a friends 6.2 powered promo boats (200 & new SN).

Both would be an amazing package in a Sport Nautique but I'd recommend you save the $$ and go with a 409. While I love the H6, the performance gains are not dramatic enough to be worth the extra spend unless you're pulling multiple barefooters on a regular basis, skiing the course on a short lake with minimal setup time etc, etc.

The conversion itself is really straightforward if you package the elements correctly. I'd highly recommend giving Tim White at a call at Inboard Solutions. They repower boats in their shop and can assist virtually. He helped us package our 409 & new 80a transmission with all the correct wiring harnesses, motor mounts, Zero Off etc. In fact, I believe he was working on a Sport Nautique while we were packaging our 409. He can also give you some additional engine options from PCM at different price points.

Also, cut-offs are banned for anyone under the age of 55, us kids of the 1960's and early '70's were the real cut-off era people!

Don't worry about any flack, I think the "keep it original" crowd stop caring around 1995 or so!

I can put 4 people in the boat and pull a slalom skier, granted the wake isn't great with all that weight but we do it routinely. I can ballast up and pull a wakeboarder with no issues, I don't think it would matter how many people in the boat. And to bomb around the lake I find my boat a blast to drive and no amount of people challenges the engine.

I only say all this because now we know you aren't looking for this to be your primary slalom boat. Why not, as someone above mentioned, repower with a custom built stroker that could use your same tranny and mounts, develop the same power as the 409, and probably sound much better? Granted maybe not the turn the key and go aspect of injection but talk about the cool factor! Anyway I totally understand if you go 409 package instead, just thinking aloud.

Dominic, interesting to read your thoughts on the repower, also being a Sport owner, mine is a '98. When looking for my boat I test drove a 502 Python powered '99 Sport, and it sounded great, power was awesome, I think it topped out at 52 or so if the Airguides were right, as compared to my GT-40 at 45-46. In the end I chose the GT-40 because we slalom and the weight of the big block wouldn't help the wake any, plus just by eye (I didn't ski behind it) I thought the 32-34 mph wake was visibly larger.

Your modern repower options sounds like they'd be outstanding upgrades. I guess not knowing what your intended use of the boat is, I'd say you might not get as much added top speed as you might expect with 100 extra HP, maybe 7 mph or so which isn't anything to sneer at but I know at times people think 100 HP would do more.

You asked about the H6 vs. 409, I can't come up with any reason to not go with the 409 for half the money if you end up with that choice.

The 6.0L has been standard on the SN for a while and has been optional since 2003... many older repowers out there as well. Not a new path to blaze. The 409 should fit under your existing engine cover.

There are rumors that the DI engines will not fit under the box, but I do not recall seeing anyone else try (yet). Big blocks definitely won’t- and in addition to being unobtainable, those would require additional powertrain hardware modifications to use reliably.

The H6 is new generation. Direct injection adds a lot to any engine. It allows full timing at all times because direct injection actually cools the intake charge cooling the piston heads and the valve chambers allowing more compression to be used for added efficiency.
The H6 is a full aluminum block and heads reducing weight.
Your fuel pump in a H6 probably has 1,500-1800 PSI of fuel pressure which allows injecting fuel with the piston at top dead center eliminating detonation risk in this engine.
The other engines use older technology, it is cheaper and they still run pretty dang well but the DI engines are next generation and cost more. I bet a fuel pump that puts out that kind of pressure will cost plenty when it breaks, I bet in the $2,500-3,500 range?
Some of the DI engines use mechanical fuel pumps that boost the fuel pressure to the required amount. Some use cam lobes internal in the engine to run the pressure up.
I do not know how GM is running the direct injection pump in these.
Having DI in an engine allows you to bump compression as high as you wish opening the door to many high performance upgrades in the future. Turbo or Supercharging is not nearly as hard to manage if you have a DI engine.

TRBenj wrote: 1” prop shaft is not a concern with the powertrain options being discussed. Standard fare in the SN.

Guess I wasn't thinking, basically he's copying Orange Crush?

I have the GT40 so very few power upgrade options. As much as I want to keep the original engine, it just doesn’t have the power I am after. I have thought about having a 460 Ford built and calling it the gt460. Might sit better with die hard Correct Craft restoration members. I mean, this boat will be restored to better than factory, all original, but I wanted something a little special under the hood.

MrMcD wrote: There is no doubt the new LS Chevy Engines are very good engines. If that is your desire do it. Assuming your 99 has a 351W engine now. If you just want more power in your 1999 boat have you looked at other options? I bet you could put a stroked 351, I think it works out to a 406? Roller Cam and bump the stock engine to 400 HP. I understand if your boat has the Fuel Injected 351W this option may not work due to the fuel injection limits. If it has a carb it would not be an issue at all, easy upgrade. When I think of a $20,000 upgrade to a 1999 I would really want to evaluate. The stroker 351W making 400 HP would be less than a $6,000 upgrade and the horsepower is pretty close to the LS conversion. If your boat currently has a Chevy for power a 350 can be converted to a 383 or even a 406 and again, horsepower could be 400+ with torque approaching 500 ft lbs for under 6,000. I turn my own wrenches so I don't add in labor charges but wanted to offer a couple things to think of. The engine upgrades also use your current tranny/exhaust and mounts saving more money. So I agree the LS GM engines are fantastic engines, my son has one with twin turbos making 765 HP at the rear tire, that is close to 900 at the crankshaft. It handles it fine and has close to 50,000 miles and runs like brand new still.   Ususally 900 HP engines are very short life. You have options that might keep a lot of money in your pocket and still offer the smile you want on acceleration.

There is no doubt the new LS Chevy Engines are very good engines.
If that is your desire do it.
Assuming your 99 has a 351W engine now.
If you just want more power in your 1999 boat have you looked at other options?

I bet you could put a stroked 351, I think it works out to a 406? Roller Cam and bump the stock engine to 400 HP. I understand if your boat has the Fuel Injected 351W this option may not work due to the fuel injection limits.
If it has a carb it would not be an issue at all, easy upgrade.

When I think of a $20,000 upgrade to a 1999 I would really want to evaluate.

The stroker 351W making 400 HP would be less than a $6,000 upgrade and the horsepower is pretty close to the LS conversion.

If your boat currently has a Chevy for power a 350 can be converted to a 383 or even a 406 and again, horsepower could be 400+ with torque approaching 500 ft lbs for under 6,000.
I turn my own wrenches so I don't add in labor charges but wanted to offer a couple things to think of.

The engine upgrades also use your current tranny/exhaust and mounts saving more money.

So I agree the LS GM engines are fantastic engines, my son has one with twin turbos making 765 HP at the rear tire, that is close to 900 at the crankshaft. It handles it fine and has close to 50,000 miles and runs like brand new still.   Ususally 900 HP engines are very short life.
You have options that might keep a lot of money in your pocket and still offer the smile you want on acceleration.

I’ve been told the 1” ARE shaft can handle the power no problem. The larger shaft found in the larger Nautiques is there for the extreme amount of weight these bots are riding around with. The Ski with a 6.2 has a 1” shaft.

As far as the dealer goes, a Nautique dealer is who is willing to sell me the complete H6 engine/trans crate. No boat information needed.

Hey CCF,

I am preparing to do a complete drivetrain replacement on my 99 Sport Nautique. I have been considering either the H6 or ZR409. I want this boat to be REALLY fun to drive. The 550 isn’t available as re-power. My dealer simply can’t order it. (I was serious about this). So I had to compromise. While I was really leaning towards the H6, my dealer got back to me today and quoted me $28,000.00+ with a 1.23:1. No labor. Just the engine, trans, and shipping. Kinda hard to swallow for a naturally aspirated engine.

In comparison with the H6, the ZR409 has slightly less horsepower (409 vs 450) but more torque than the H6 (492 vs 465). The only major difference I can find between the two is the H6 has direct Injection and is .2 liters larger.

I found the ZR409 at Discount Inboard Marine for half the price of the H6 with the trans. I’m just trying to justify and understand the cost of the H6. Because this is my project boat (passed onto me from my dad, will be passed onto my children) cost isn’t so much of a concern and I am already prepared to make major modifications to engine mounting, etc. Either way, the extra cost of the H6 has to make sense. Especially if the ZR409 is going to give me better performance. I would think torque would be more important for a heavier boat like the Sport Nautique.

I appreciate anyone’s feedback.