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Modifications to 7.4L (non-mag)....Opinions/Help Please!

GTkiller97

GTkiller97

New member
Hey guys i currently have my boat for sale, i am thinking hard about taking it off the market and just doing some things to make it what i want (faster!!!). I have been looking into Superchargers on Jegs/Summit and have found a few that are just under 3k, not bad really. I also have been thinking about maybe just doing a intake,cam,carb kit instead which should be much less. Just want to know what your guys thoughts are on the situation. I'm not looking to go crazy on a big build or engine swap, just want some extra HP's...Boat runs about 55 GPS and i'm looking for 60+ with some good midrange power as well. Thanks!
 
GTkiller97 said:
Hey guys i currently have my boat for sale, i am thinking hard about taking it off the market and just doing some things to make it what i want (faster!!!). I have been looking into Superchargers on Jegs/Summit and have found a few that are just under 3k, not bad really. I also have been thinking about maybe just doing a intake,cam,carb kit instead which should be much less. Just want to know what your guys thoughts are on the situation. I'm not looking to go crazy on a big build or engine swap, just want some extra HP's...Boat runs about 55 GPS and i'm looking for 60+ with some good midrange power as well. Thanks!
Click to expand...

I just saw a thread about this on OSO. Here is what one of the guys over there had to say for good power on a budget. I copied his post and i am pasting it below:

"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 would not supercharge that engine....cast crank, cast pistons, ect. Change to forged flat topped pistons, find a set of take-off GM 088 rect. port heads.......nice rect port intake to match....the holley carb and a medium cam. The stock exhaust is very restrictive and you wont see much in gains without finding a nice set of performance manifolds.....don't forget to upgrade the oil cooler too...the stock ones are tiny.
 
Gimme Fuel said:
I would not supercharge that engine....cast crank, cast pistons, ect. Change to forged flat topped pistons, find a set of take-off GM 088 rect. port heads.......nice rect port intake to match....the holley carb and a medium cam. The stock exhaust is very restrictive and you wont see much in gains without finding a nice set of performance manifolds.....don't forget to upgrade the oil cooler too...the stock ones are tiny.
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When did your motor run last?:poke:
Your right though non mag motors are not a good start.
 
Engine swap.

A solid engine is worth money. If all the pieces are in good order, I'd consider an engine swap.

The problem is that this makes the most sense around November, when shops want winter work. Lots of upgrades start racking up the dough, so maybe put the bug into an engine shop's ear.

It's just an idea. I did all the math one time and honestly calculated the cost of the trouble to hot rod and care for an existing motor vs getting a new one and selling off the old one. An engine swap made more sense.

Just a thought. The 454 and 502 are the same config, so you might want to consider a 502. You can add 100 HP and the new engine would be asleep carrying that extra HP and extra torque, or forced some xrtra into your engine now.

I have outboards on the brain now... so someone back me up on the 454/502 thing.
 
I agree on the engine swap...find a take out 502 mag direct bolt in...a HP500 would be the ticket !
 
ezstriper said:
I agree on the engine swap...find a take out 502 mag direct bolt in...a HP500 would be the ticket !
Click to expand...

That's the route I went and gained 10 mph without switching the exhaust
Probably would have got more w good exhaust those 330s are really reliable stock but don't hold up well to upgrades also everyone is forgetting that you are going to have to change ignition setups to see the gains of the better flowing heads and better cams stock 330 ignition will shut you down at 4900 rpms
 
x2 Gimme Fuel . In my opinion steel crank and rods are mandatory to keep it all together. You probably would want to shoot for 500hp in the 253 min. or keep what you have, reliabilty.:thumb:
 
Problem Child said:
x2 Gimme Fuel . In my opinion steel crank and rods are mandatory to keep it all together. You probably would want to shoot for 500hp in the 253 min. or keep what you have, reliabilty.:thumb:
Click to expand...
basically with that engine you have a good.....block.....and thats about it as far as a performance motor goes. 454 block are easy to find and can be gotten cheaply used. If you want to have the joy of building a motor, do yourself a favor. Find a good used truck block and start your new motor on the stand while you run what you have until it is ready. Speaking from experience here.

You can get new forged rotating assemblies from Ohio Crankshaft very reasonably so you might as well put together a 496 stroker. Then if you still want a supercharged motor, you can put on the 088 gm heads, which can also be found cheaply used, get a nice blower cam, bolt on the blower and let it make up for the lesser cubic inch and mild heads. Things get expensive trying to make power naturally aspirated. you will have a lot of money into it to try and make the big power. Used rebuilt blowers can be bought for what a good set of heads will run you. Just start one on the side and start piecing it together...dont rush it, and take enough time to build ultimately what you want....so you are satisfied.
 
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