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mild 454 upgrades?

Old 05-29-2012, 06:14 PM
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Default mild 454 upgrades?

i have a 454 i will be installing this winter to my boat and want to do a cam and heads and intake on the motor. the motor is just a standard 454 with 330 hp and want to take it up to around 400hp. what cam and head spec does eveyone use along with intake manifold spec. the motor is now in carb for and ill keep it that way. im only keeping the boat for this season and next so i want to stay cost effiective. im going from a 350 and alpha so ill be happy with a mild 454 until i get a new boat.
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Old 05-29-2012, 06:35 PM
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I really don't think you can build a low cost 400 hp engine out of your 330. If your lucky you'll gain 4-5 MPH and it will cost you at least $4000 by the time to have the needed machine work to the block, new bearings, cam bearings, rings, cam, springs, heads, exhaust, ect. It's not as simple as just buying a cam, intake, heads. I had a set of heads that had 230 hours on them, expected a simple valve job. $900 later I have a complete set of heads.

Do yourself a favor, leave your boat alone a 60 hp increase isn't worth the time, effort and frustration in my opinion. Also- your alpha will not live long with a 400 hp BBC in front of it. So add another $2500 for a bravo set up.
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Old 05-29-2012, 07:56 PM
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I believe they only used the standard 454/Alpha package for a year or two before they gave up on that combo. If the 350 is in good shape and has the standard iron intake just going to the high rise intake from the 350 magnum, adding the taller magnum flame arrestor, and using the magnum secondary rods will give you a nice boost that you can feel both in acceleration and top speed. I agree w/endeavor32. The 454 will be spend y.
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Old 05-31-2012, 10:06 AM
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i have the 454 and bravo package already and before i was gonna put it in the boat i was gonna see if there was some mild upgrades to boost a bit of performance out of the motor before i install it in the boat. thats why i asked i dont mind spending a few bucks for some bolt on power.
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Old 05-31-2012, 10:18 AM
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Put it in as it is. If is a simple bolt on, you won't notice the difference. Remember it takes 20 HP to gain 1 MPH. So a few simple bolt on parts won't really do a thing except give you a headache!
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Old 05-31-2012, 01:18 PM
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ok cool thanks for input
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Old 05-31-2012, 06:26 PM
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I am just getting done doing what you asked about. Granted I'm not building a high hp motor, but I expect decent gains out what I've done. I build the motor last year and it has 95 hours on it and still running good, but I wanted to add some hp. I have no results or gains yet, because I'm in the middle of finishing up the motor and installing it this weekend. It hasn't cost me much at all, but I do have access to a machine shop. Even if I didn't it wouldn't be bad. I tore the block down and checked the bearings. They looked brand new so I am reusing them. The rings I went ahead and changed because rings are cheap and I had a over heat issue in the first couple of hours on the motor due to b1 lower unit corrosion clogging up the water inlet to the sea water pump. The motor showed no signs of wear so on to the (hopefully) power adding parts. The 330 hp motor comes with peanut port head which are garbage for any kind of potential hp (so I'm told). I had access to a set of 781 large oval iron heads that I installed 2.18 intake and 1.88 exhaust valves. Also ported, bowl hogged and gasket matched the heads, 3 angle valve job and then decked them flat. Next is a pro comp high rise dual intake that I ported and gasket matched to the heads. That was a bit of a pain in the a*% because pro comp intake (parts) are cheap and the casting was off a good bit, but after some time and effort it turned out real nice. Either way, bbc intakes are a dime a dozen and can be had for good deals. I run in fresh water so don't have the issue with salt like you may or may not have. The cam I have is a .506 intake 510 exhaust 224in 224 ex duration. I was told it is a factory style 500 mpi cam. I wanted to go larger, but at this point its what I've got to use because I don't want to spend the money on a roller setup for this build (plans for a 540 over the winter). I have been questioning what carb the last few days and the general reply is that my q-jet is good enough for this mild build so I'll just get a new one for my winter project and leave the g-jet on. Also added a double roller timing set with roller cam button as the motor had some kind of POS timing set in it.

I have no idea what kind of power this motor will make, but I'm sure it will be better then my dump truck headed motor I had last season...LOL Again, this isn't much compared to the huge motor builds I read about on here, but I am being told it will be a noticeable difference compared to the old motor and I don't have much money in the build what so ever.

I hope to have some before and after mph results after the weekend (good or bad).

Good luck with what you decide.

Sorry for the book.
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Old 05-31-2012, 07:40 PM
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Took 20 hp per mile per hour to increase the performance of my Chris Craft Stinger 260. That was from 58 to 62-63 m.p.h. It took heads, cam, intake, flame arrestor, carb jetting for the Q-jet. Also added 4-bolt blocks, steel crank, and pink rods, HD oil pump to handle the increase HP. Had to buy larger props too. If I feel the need for speed again I'll just buy a faster boat! I didn't get a penny extra when I sold the ChrisCraft. Still, it's fun increase the performance. I do understand!
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Old 05-31-2012, 08:38 PM
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Few things. Before you want to do any kind of upgrades, I strongly suggest getting a decent aftermarket exhaust.

As for the 330HP. There are many ways to "hop" it up. The 330HP 454 had alot going against it.

Peanut port truck heads.

Cast iron intake manifold

Dished pistons=low compression

Wimpy Cam.

Now, if you wanna get serious, going to a set of later style BBC vortec heads, will net you some power, for not alot of money, if you can find a set reasonable enough. The vortec head has a smaller chamber, which will bump your compression up at least a full point. I wanna say they were around 8.0:1 Stock with the standard 119 chambers. The vortec head will flow better than the heads you have now. I'd say bolting on a set of vortec heads, between the full point of compression, better chamber/port design, 50HP gain just from the heads isn't a crazy thought.

A cam swap. No need to go crazy here with lift and duration, but a mild performance marine cam, will be a good improvement. Stock 330 cams were just wimpy.

Intake manifold. A aluminum dual plane, that matches the vortec style head would be good.

A single holley 750 double pumper would work fine.

Properly spec'n a engine like this, with the right combo, 425HP isn't out of reason. I know of several guys who've hopped up the old 330's with good results, for cheap money. Granted it's not gonna be a 6000rpm 600HP engine, but it's still a 454CI big block, and less than 1 hp per cubic inch isnt asking that much. With the cast crank, you'll wanna keep the rpm at about 5000-5200 max. I remember a few oso members doing these upgrades back in the day, and were pleasantly surprised with the results.
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Old 05-31-2012, 09:12 PM
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I am kinda +1 on Mild Thunders recommendations above. Good moderate cost way to add about 100HP to a good condition 330HP short block. With a good standard Bravo 1 drive, proper prop and such you should see about 6-8 miles per hour more speed, a better cruise speed and some much stronger accelleration. Probably a lot cheaper than a new faster boat and you'll get more enjoyment out of the boat while you own it.

Best Regards,
Ray @ Raylar
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