New Guy with Questions
 

Hello, I recently purchased a 1995 Superboat 24. It has a 454mag Bravo 1 with about 200 hours on it. I was wondering what could be done to pick up some speed without loosing my low and midrange. It already has K-planes and a Stainless Marine exhaust. Currently running either a 24” Bravo or a 25” Mach. I was thinking of leaving the cam, adding some Edelbrock Performer RPM Oval port Heads, Performer RPM Air Gap Intake, Demon Carb and doing some ignition work. The boat will be run in fresh water, Great Lakes. Any suggestions you could provide would be great.
Thanks,

Re: New Guy with Questions
 

You should be thinking 540. And the price is rite. If you want to go fast give me a PM

Re: New Guy with Questions
 

Sounds like a cool boat. Post some pics. I'm not much of a motor guy but I'm sure others will chime in soon.

Re: New Guy with Questions
 

Razor,
Welcome to the board and congrats on your purchase. :drink:
I like the selection of parts that you have listed, but without a cam change, your engine is not going to gain much power at all. I would also suggest that you overhaul the bottom end if your going to up the anti. Rings, Bearings, an oil pump, and a few more gaskets are well worth the extra on a 10 year old engine.
There is a lot of knowledge over in the TQ&A forum if you want help selecting parts. Or a few of us armatures here will give you an opinion.
Zuperboat has a 600HP engine for sale that would push a 24' Super near 90mph. It probably would not cost a whole lot more than rebuilding yours to make 450HP.
Good Luck!

Re: New Guy with Questions
 

Bolt in Zuperboats mota and hang on,don't say "its to much power" you don't have to use it all, it's more than worth what he's asking,you wont be sorry tripps

Re: New Guy with Questions
 

That was a little more than I would want to spend at this time. I was thinking that a few bolt on could make a big difference. How long does a shortblock in a boat last? I didn't think 200 hours sounded like a whole lot. Edelbrock claims 500 hp with their RPM setup on this motor. I figured without changing the cam, I would see 450 hp and close to 500ft/lbs with a pretty flat torque curve. Possibly move the boat up to around 80mph and not put too much stress on the Bravo1 drive. I guess I need to do a little more research.

Re: New Guy with Questions
 

Tripps did I read somewhere that you were in the Bahamas ???

Re: New Guy with Questions
 

My 2 Cents Says If You Put A New Upper End On An Old Lower Your Going To Blowout The Lower. Heads And A Cam May Make 500hp But At What Rpm. With A 454 Your Going To Have To Spin It Around 6ooo To Get 500hp. Add A Dominator And Make A Few More Ponies, But You Loose The Torque. Its All About The Torque. Don't Look At The Hp Number Look At The Torque Number. And To Get Good Torque You Need Big Cubic Inches. My 540 Made If I Remember Correctly 700 Foot Lbs @ 4500. Sell What You Have And Go Rite To The End Of Your Journey. Otherwise You Will Be Adding Parts For The Next 5 Years And Still Have A 454. DID I FORGET SPECIAL HEAD BOLTS FOR THE NEW HEADS ANOTHER $150 ROLLER ROCKER ANOTHER $300 CORRECT LENGTH PUSHRODS ANOTHER $200. NEW VALVE COVERS TO CLEAR THE ROCKERSANOTHER $200

Re: New Guy with Questions
 

Zup has made some good points.
I've been there done that/doing that... :rolleyes:

When I bought my 24' three seasons ago I bolted in a 310HP/7.4MPI. She ran about 65. For the second season, I boosted up the 454 with head and valve-train work; didn't touch the bottom. She ran 70 a few times before it blew... :(
This past season I rebuilt a stock 415HP/502MPI. She will now run 75mph, but I am now thinking I'd like to go 80+. I'm going to leave it alone for another season before I build a 500HP/502... :cool:

So What is your budget?
If you are going to build up your 454, are you able to do most of the work yourself?
You have listed about $3000 in parts, but believe me, you won't gain anything without changing the cam.
The heads you have listed are indeed good for 500+HP, but so are the heads that are on the engine now. I would suggest that you spend the $$ from the new heads you planned for on rebuilding the bottom and for a new full roller valve-train...
To push a 24' Superboat 80mph, you will need a minimum of 450 prop shaft horsepower. This translates to about 500HP at the crank on a dyno with no accessories and headers...
A 454 is capable of making 500+ftlbs of torque and 500+HP but it will need the right combo of parts. And like Zup said, be a high revving engine (5600-5700rpm).

If you want to here me babble on some more, just ask... :drink:

Re: New Guy with Questions
 

Babble Babble Pat There Is More Than 3000 In Parts Heads 2k With What Valves/3 Angle Valve Job Is No Good For A Boat We All Know That.intake Is 250 Carb Another 600 Plus,ignition Is Another 600 And No Cam Yet. Rockers/rods/bolts Another 600 Almost 4500 Already . My Roller Cam Was Almost 1000. Babble Babble

Re: New Guy with Questions
 

Zup, I am going to disagree and then agree with you...
Razor listed the following:
-New Edelbrock marine heads $1500
-Add springs, retainers, and locks $250
-New Intake $250
-Carb $600
-Ignition mods? New DUI or MSD $300-$600
Total around $3,000.

Now, add to that:
-Rebuild (rings, bearings, oil pump) and Balance short block $1500
-Full roller valve-train $1,000
Yup, you might sell your 600 for $5,500... :drink:

Re: New Guy with Questions
 

Thanks for the responses: I still have a few questions though.
The parts I am/was looking at come to around 3,200 with the roller rockers, complete heads, carb, intake, and all the gaskets. This is what I could do myself without pulling the engine. Does anybody know the flow numbers on the stock heads? If my peak horsepower is 350/365, what is the peak torque? And what is the curve like? I would love to see a dyno sheet of this engine stock if anyone out there has one. I'm not a big horsepower guy, the parts I listed should get around 500 ft/lbs at the crank and stay over 400 through out the curve (1500 to 5000). I am also not looking to push much past 5000 with a rev limiter set at around 5200. I do not want to get to the point that I am worried every time I go out that I may blow out the lower half or the outdrive. I just figured that a 454 mag with forged internals should be running more than the 365 HP that it currently has. I am not looking to pull the motor just yet, when I do I would likely switch to a 502 shortblock. I figured this upper half would work nicely with the new 502 shortblock once it is needed. Am I wrong in thinking that higher flowing heads with the stock cam (I believe 224/224) would give me a substantially more low-end torque? I just really like strong running engines. How much power should this lower half be able to hold at 5000 rpm’s with 200 hundred hours on it? I was hoping for an additional 75 to 100 hours. If the lower half cannot hold the power, I will wait to do anything. Ok, one last question. If I make the engine change later, will my drive with 10 years on it need to be replaced?

Thanks again for all the info,

Re: New Guy with Questions
 

200 hrs is about 1/2 the life of the motor. 365 is a good start, has all the good internals. If you have good semi dry exhaust I have a hydrolic crane cam that I loved. Its the merc 575 cam I will have to try to get the numbers. Probably $200 for cam and lifters.Ask Pat if you can do a cam change in the boat. A cam will wake up the motor. You will probably get more from a cam than a head with this setup.If your buying heads dont buy a large intake port size stay under 310. Works better for lower rpm and will make more torque. Best heads out there are the AFR but pricey.How big is the carb. A holley 800-850 will work. Any way best of luck. MIKE

Re: New Guy with Questions
 

Razor,
Highperformance Chevy magazine has the flow test numbers for your rectangular port heads. You can find them on-line...
I'm not sure if you have a Gen V or Gen VI engine; 1995 is the transition year. Either way, peak torque is about 450ftlbs. The 365HP @ 5000rpm rating is at the prop shaft. You have a bit more than that with the better Stainless Marine exhaust. On a dyno, max HP would be 400-420 @ 5000-5200rpm...
The components used in your short block are good for about 550HP @ 6000rpm if checked and balance properly.
Yes, if you bolt on a set of large oval Edelbrock heads, your engine will make more low end torque. But, I'm going to repeat myself, without a cam change, your waisting your time and $$. A Gen V 454Mag/OH cam is 220°/220°, .500/.500 lift and a Gen VI is 224°/224°, .480/.480; vary mild.
If you want your engine to make 500ftlbs and peak HP at 5200rpm, rebuild to something similar to the Merc 425. The cam in that engine was something like 230/236, .550/.560.
A 425 would push a 24' Super 76mph, 77tops... :drink:

Re: New Guy with Questions
 

Ok, Now I understand that the Head's are not the weak point. I will change my search to a cam, intake and carb. Will I have to have the engine pulled to change the cam? If I am not able to pull the engine at this time, would changing the intake and carb make any difference (positive benefits) at all?

I really do appreciate all the info.
Thanks,

Re: New Guy with Questions
 

I did change the cam in my boat last year but it's not easy.
You have to drop the oil pan. With a cam change comes new valve springs and a valve job so you'll be pulling the heads too.
If your 750 cfm Carter carb is working well leave it unless you change the cam. If you are having problems with starting, some people do with them, buy a 800cfm double pumper that will work with mods up to 500HP down the road.
The intake you have is a good one, so don't change it unless your going to build a 5600rpm screamer. In that case you will need a single plan...
Have Fun! :drink:

Re: New Guy with Questions
 

Hey! wait a minute! :evilb: :D

Re: New Guy with Questions
 

Yes Dave, your 1998 stepped pad hull is 1-2mph faster than my 97 or Razors 95 straight V... :p

Re: New Guy with Questions
 

The cam in that engine was something like 230/236, .550/.560.

OK, 425/500 is a lot beter than where I am. Who sells the cam and what valve springs to go with. Why the valve job? Should I look for a set of reworked heads already done?

Re: New Guy with Questions
 

Razor,
The Merc 420HP/454 was a Gen IV engine and the 425HP/454 was a Gen V version of the same engine. These engines were basically 454mags with a hotter cam, roller rockers, single plane intake, 750cfm Holley double pumper, and Gil exhaust. The cam was a hydraulic flat tappet made by Crane. You can find it easily on their web sight. Merc also used this same cam in the 525SC.
First you need to figure out if you have a Gen V or Gen VI engine. Gen IV and V engines have a sheet metal timing chain cover with 10 bolts. Gen VI engines have a cast aluminum cover with 6 bolts.
If you have a Gen V engine, the Merc/Crane 425 cam with roller rockers would be a great upgrade. The Gen VI engines have a roller cam so I would not suggest stepping back in time to a flat tappet cam. Merc never built a high HP Gen VI 454, they offered a 502 instead. However there are lots of good choices for roller cam upgrades.
Why a valve job you ask, well IMO it makes good sense with a cam change on a 200 hour engine. Just like I suggested that you do rings, bearings, and an oil pump in the lower if your boosting the overall power. Don't buy another set of heads, yours can be gone through for a few hundred $. They have good valves already so just have them clean up and install new springs, retainers, locks, and seals. Hell, I had mine bowl ported for an extra $200 last year.
Razor, I understand that you want to just bolt on a few new parts and go a little faster, but it's not going to happen. The only bolt on goody, other than a supercharger, that really helps is a better flowing exhaust. And you already have that.
Pull the engine out and do the job right or just leave it alone and enjoy.

Re: New Guy with Questions
 

That is correct superbabi,i was in the Bahamas last week,tried to get to Key West,but that didn't happen tripps

Re: New Guy with Questions
 

We were there the week before you tripps, where did you stay ???

Re: New Guy with Questions
 

Pat the timing cover should come off with just loosening the pan bolts not lowering the cover. Done it many times over the years. As for valves I dont believe that motor would come with the good valves that he needs. Ive broken more than one valve in my day. I would agree with you on heads dont buy used junk. Now for the cam Im looking tonight for the merc 575 cam specs. It pulled hard to 5700 rpm for me. If he has the stock merc aluminam dualplain intake , that will work great to 5500 add a 1 inch spacer. if its a spread bore intake they sell an adaptor spacer for that to put a holley on it properly. A cam/valves/carb =450-475hp

Re: New Guy with Questions
 

Zup, if the engine is a Gen VI like mine, you will end up leaving the pan hanging by just a couple of bolts at the rear to get the timing cover off. Lucky the back seat comes out on the 24 Super to give good access. I still would pull the engine next time...
I was told by two builders last year that the stock valves in the magnums are ss intake and a 2 piece inconel exhaust. No, not as good as Manley severe duty.
The Merc 575 cam is about the biggest hydraulic flat tappet cam that will work well. A great choice to boost a Gen V 454 to make power all the way past 5800rpm. Like you said yesterday Zup, you need the long risers to run it though.
The intake that is on a 1995 454mag is a spread bore with a 1" 4 hole spacer under a 750 cfm Carter carb. A Holley or BG will go right in place of the Carter, but for higher RPM I would suggest an open spacer. What do you think Zup?

Re: New Guy with Questions
 

Superbabi,we stayed at the Harborside which is a part of Atlantis,too bad the water up here isn't as nice as the water down there!!! I'm goin next year the week you went,are you goin that week again?? tripps

Re: New Guy with Questions
 

We stayed at the RIU ( old sheraton ) Very nice, right on the ocean !!! Tripps is the harborside the 2-3 story units, multi colors, directly on the harbor ????

Re: New Guy with Questions
 

The spacer to buy is a 4 hole tapered spacer. They work the best torque. My bud built a 496 with a 750cfm for a guy that didnt want to buy a carb and made like 565hp. Carb was way to small. The builder said he will buy an 850 and if the power doesnt inprove he will eat the the carb. On the redyno it went for 565hp to 590hp and the customer was very happy to pay for the carb. So my though is an 850 double pumper with big acc pumps. Now for the intake, if your going to spin your 200 hr motor that you know nothing about the history of at 5000rpm go with the duel plenam. If your going to be brave and spin it around 5600 then go with the open plenam.

Re: New Guy with Questions
 

OK, It does not look like I will be replacing the lower half anytime soon, so so I guess more power is not an option. I was really trying to make a difference with only around $3,000. Looks like I will need at least double to triple that. My question now would be, is my boat worth that type of upgrade? I know a lot of you guys are doing it. This is a lot to think about.

I have always wanted to race, can this boat compete in a P5 class the way it is? What would I need to do, to prep this boat to run P5/P4?

Please don't dell me replace the lower half. (lol)

Thanks,

Re: New Guy with Questions
 

Razor, I did a basically stock rebuild on my 502 last winter for about $2,000.
This included the following from a local machine shop/builder:
-clean, hone, install new freeze plugs, and cam bearing in the block $200.
-the heads were cleaned, mag'd, milled 0.010, bowl ported, valve job, new springs, retainers, locks, and assembled $800.
Then I bought new rings, bearings, a Merc gasket set ($450), and an oil pump for about $900 total. Throw in and $100 misc. I bolted it together myself... :D
Now for another $1200, the engine builder would have assembled the entire engine and given me a 1 yr warranty on the long block, but what fun would that have been... :rolleyes:
Razor, I believe you could do a vary nice build up on your engine for between $3,000 and $4000. If you want to risk it and leave the bottom alone then $1500 in parts can give her a little more kick. :D
Anther 50HP will give you +4 to 5mph, another 100HP +7 to 8mph.
As far as racing, P-5 has a 70mph limit, but I think the boat is too small. Ask fasteddie... :drink:

Re: New Guy with Questions
 

Thanks Again,
I do not feel I could pull and place the engine myself. I am really not to worried about the lower half blowing, especially with a 50 HP increase. But if I will have to pull the engine to change the cam, I don't know.

I just back through all the older stuff you wrote, looks like you did a lot. I wonder if I should be bunning a 26" Bravo1 prop?

Re: New Guy with Questions
 

Dave M. ran a 26p B1 when his boat had a 385HP/454MagMPI. and I ran a lab finished 26p B1 with a modified 340?HP/7.4MPI.
Both Dave and I run 28p B1s now... :D
A stock 454mag makes max power at 5000rpm so that is what you want to prop for... :drink:

Re: New Guy with Questions
 

Razor, figure out if you have a Gen V or Gen VI engine. Bulding 50HP more is pretty straight forward.
If you have a Gen V then use the Merc/Crane 420,425,525sc cam. This cam is what most guys use when building up Gen IV and Gen V low output 454s.
If you have a Gen VI engine then I would consider using the ZZ502 crate motor cam. After-market roller cams and lifters are big $$, but the GM stuff is not.
You will need to replace the valve springs to match the new cam, and the non-adjust rockers with an adjustable setup.
If you decide to have a valve job done, have the heads milled at least 0.010 to boost the compression a little.
And like we've talk before, you will need a double pumper carb and ignition changes.
Have fun with it... :drink:

Re: New Guy with Questions
 

Mine is a Gen V, non roller cam. I will take a look at the Crane cams. Is a Demon carb worth the money? Will it bolt up to my intake manifold (do they make an adapter)? When it is time to do the shortblock, I may make the change to the 502. I just want to make sure everything I look at is good for the switch.

Re: New Guy with Questions
 

Since, you have a Gen V, a full roller cam setup does get costly. I'd stay with a hydraulic flat tappit cam and add roller rockers...
I work with a fellow that bought a Demon for his car and loves it; he said it was much easier to setup than a Holley. Personally I have no experience with them.
I believe that your GM/Merc intake will except both bolt patterns and does not require an "adapter". It does require a spacer to cover the larger secondary openings meant for a spread bore carb. I think you have a 4 hole spacer under your Carter square bore carb now; if not, you should.
You could just re-jet your 750 Carter to try with the bigger cam. Merc used the same carb and intake on the 390HP/502. The only difference was the jetting and an open spacer. A 750 carb is good to about 5200rpm on a 454.
If you do decide to buy a new carb, my first thought is to buy the same Holley 800cfm carb that Merc Racing used on the HP500/502. Lots of places sell them so you can get a good deal. The Sea Demon comes 750 or 850, so if your thinking bigger cubes down the road, 850...

Re: New Guy with Questions
 

Superbabi,yes that is where the harborside is,a nice clean place,i'll be goin back next year,are you?? tripps

Re: New Guy with Questions
 

Tripps, what one were you in ???

Re: New Guy with Questions
 

Razor your boating expences have just started. better get use to it. every year you will be adding more stuff. Superbabi had a quize a while back . What does B.O.A.T. stand for ?

Re: New Guy with Questions
 

"Bring On Another Thousand"
or "Break Out Another Thousand"
or was it "Break Out Another Ten thousand"... :eek:

Re: New Guy with Questions
 

Razor, full force boating will..................SUCK YOU DRY !!!!!!.............Ahhhhhhhhhhh gotta love it. :evilb: :evilb: :evilb:

Re: New Guy with Questions
 

Super,the one that is facing the Atlantis by the dock. You can get basicly anyone you want,book on a saturday arival and you get a view of the pool,so you can watch the kids in the pool as you sip Kiliks from the baloncy :D :D :D tripps