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mild 454 upgrades?

Old 05-31-2012, 09:49 PM
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Thanks ray!
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Old 05-31-2012, 09:56 PM
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A nice upgrade would be to install a gen vi roller magnum cam. Competition products sells new takeout billet roller 454/502 magnum cams for 35 bucks. A set of street roller lifters would suffice. You'll need a gen vi timing set to make it work, and a electric or sea pump style fuel pump, as that cam has no fuel pump lobe. That cam would be a nice upgrade from what you have. Plus, you get to go to a roller setup. Not that much more than a new flat tappet marine cam, lifter, timing chain setup.
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Old 05-31-2012, 09:57 PM
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i just did the upgrade 2 yrs ago on a 454, 781 oval port head with bigger valves, performer rpm intake, bigger roller cam, 496 exhaust, I ran the qjet 1 season then changed to a new 800dp holley and it really woke it up, I was really pleased with the power upgrade for the money, but I had a roller motor (1996) so I did reuse the lifters, I can get you the cam and spring numbers if interested. The motor was dependable still.
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Old 05-31-2012, 11:02 PM
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Reading all the replys give me hope for my own build that I'm finishing up. One thing that I was unaware of is that the 330 hp motor came with a dish piston. My motor wasn't a factory mercruiser 330 engine. It was just thrown together with parts that were available to me. It is a 4 bolt block with a cast crank, 3/8 rods but I used a set of new flat top hyperutectic pistons. Hopefully the flat tops will work in my favor over the lower compression dish pistons.
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Old 06-01-2012, 07:40 AM
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My engine is a .60 over 330 short block with flat tops, 188 heads, Isky 270/280 cam (mild cam) roller rockers, edelbrock performer intake, 750 edelbrock carb. It made 407HP/427TQ at 5000rpm on the dyno. We had to put in the biggest jets that edelbrock makes for the 750 carb so it wouldn't run lean, my guess is you will need to do the same with the Q-jet.
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Old 06-01-2012, 09:45 AM
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Originally Posted by MILD THUNDER
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.
I did the above w/ 496 manifolds, ported vortec heads, air gap & 454/502HO cam. Went from stock 3 blade 21p prop to a 23p 4 blade.
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Old 06-01-2012, 10:27 AM
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When boaters like yourself come on OSO with questions on build threads like this PLEASE give all your pertinant information on what you have done, are doing or are going to do hopefully in your first post!
Dribbling after this first post with this information after generous contributors here try to give you viable information and then somewhat realize you have different specs and build stats than your first post indicated.

Your comment that this block is "being thrown together" makes engine builders like myself shudder and laugh.
NEVER expect great results from a marine performance engine build when you "throw an engine together"

In my opinion you might have limited your build up potential and long term sucess by using what is a weak base specification of cast crank, small rods and hypereuctectic cast pistons. I would not recommend putting a lot of top end money into this base block and expect to run 400+HP reliably long term with that base build.

This why I feel questioners like yourself should come on to these forums and ask your questions about initial builds before you start and sometimes get yourself into limited performance direction.

I know sometimes limited knowledge marine performance engine do it your selfers do not like to hear this type of criticism, but if specialists and successful engine builders here on OSO are going to really help you, YOU SHOULD LISTEN & LEARN !

Learn from experts and then emulate" "
"plan your work-work your plan"

Best Regards,
Ray @ Raylar
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Old 06-01-2012, 11:16 AM
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Originally Posted by Raylar
When boaters like yourself come on OSO with questions on build threads like this PLEASE give all your pertinant information on what you have done, are doing or are going to do hopefully in your first post!
Dribbling after this first post with this information after generous contributors here try to give you viable information and then somewhat realize you have different specs and build stats than your first post indicated.

Your comment that this block is "being thrown together" makes engine builders like myself shudder and laugh.
NEVER expect great results from a marine performance engine build when you "throw an engine together"

In my opinion you might have limited your build up potential and long term sucess by using what is a weak base specification of cast crank, small rods and hypereuctectic cast pistons. I would not recommend putting a lot of top end money into this base block and expect to run 400+HP reliably long term with that base build.

This why I feel questioners like yourself should come on to these forums and ask your questions about initial builds before you start and sometimes get yourself into limited performance direction.

I know sometimes limited knowledge marine performance engine do it your selfers do not like to hear this type of criticism, but if specialists and successful engine builders here on OSO are going to really help you, YOU SHOULD LISTEN & LEARN !

Learn from experts and then emulate" "
"plan your work-work your plan"

Best Regards,
Ray @ Raylar
X2 on the above!
Either way, putting money into a 330 base engine is money not wisely spent. Your very limited as to what you can do and 400-425 hp is its realistic limit. If your already looking to increase your power, once you run the 425 hp engine for a season your going to want to increase the power again. Problem is everything you now sunk money into is maxed out. So now you can give the engine you just built away for pennies and start all over again. If there is one thing I've learned over the past few engine builds its to start with a good foundation. You can always add aftermarket heads, bigger cam later for nominal money later if you want. But if you sink a bunch of money into a sub par base you're just flushing money down the toilet.
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Old 06-01-2012, 09:07 PM
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Raylar you being a professional have you ever built a motor for a customer and it come apart
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Old 06-02-2012, 08:35 AM
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It was the valve train that was the cause of failure on my original 330 (dropped #7 exhaust valve). My new engine was a budget build (I'm enlisted military so this is a expensive hobby for guys like me), got the rebuilt 330 short block at a good price used all ARP studs and bolts. I got the 188 heads rebuilt with stainless and inconel valves for a good price from HTG motorsports (why go with peanuts again) I put a small Isky cam and lifters in it, roller rockers, one piece push rods, a used edelbrock intake, sprung for the new edelbrock carb, hi-volume oil pump, 10qt oil pan. I only spin it to 4800rpm and not often, I mostly cruise. Yes I spent a little more on valve train but that was because that was the failure in my original engine.

I see no reason why my engine is not reliable, and it cost the same as a re-manufactured 330 long block.

I was on a budget so no roller cam, just the standard Isky cam. With the money I saved from the cam I had the engine professionally broken in and tuned on the dyno at Orlandi Performance. And a good thing I did, I would have never known the engine was running on the lean side with the stock jets in the Edelbrock carb.
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