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-   -   upgrade a 7.4-330hp? (https://www.offshoreonly.com/forums/general-q/258349-upgrade-7-4-330hp.html)

Kidnova 07-19-2011 09:06 PM


Originally Posted by 95caliber (Post 3456083)
Just bought a 23 nova and might turn it up this winter. Is my 7.4-330hp a workable platform or should I look for something else? Looking for 500hp, what are my options?

I bought a 1995 23 Nova about 9 years ago. It also had the 7.4 in it. Boat ran 56-57 mph. Speedo said 62, but I believe it lied.

I don't know how fast you want to go, but a 23 Nova was not designed to go super fast. I'm now running just shy of 700 hp and my Nova is stable/safe/predictable into the low 70's in a 2 foot chop. Any faster and you really need to stay on top of it. Fastest I've had it going is a tad over 83. With some set up work, shortie, labbed prop, bla bla bla, I'm sure it would get to the high 80's with no problem. But to me the hull is not designed such that it's worth sinking the $$ into it to go any faster.

That said, I wouldn't sink a ton of $$ into the engine unless you plan to keep the boat for a while. My 1st mod was taking out the 7.4 and dropping in a ZZ502/502. Boat would do 70 gps any day any time with the ZZ502. Topped out at 73 gps. IMHO it was the perfect engine for the boat.

Hope this helps with your decision.

Kidnova 07-19-2011 09:09 PM


Originally Posted by 1BIGJIM (Post 3456260)
$2,500 will not get you very far:eek:
Just a small list....
$1,000 for a good roller setup
$800-900 for a decent crank, 4.25 stroke
You will need good rods $450
Pistons to go on those rods $550 Rings $100
Bearings to spin that crank $125
Oil pump to oil the bearings $75
If you need exhast plan on used or $2k + for new.
New oil cooler for your bigger power
Heads with good valves and machine work 1k - 2.5k
Proably want roller rockers on the new heads
It goes on and on if you ever built one:drink:

Don't forget about machine work $500 +

Just saw this post, and..... yep, and then some LOL

jeffswav 07-19-2011 09:12 PM


Originally Posted by Kidnova (Post 3457118)
I bought a 1995 23 Nova about 9 years ago. It also had the 7.4 in it. Boat ran 56-57 mph. Speedo said 62, but I believe it lied.

I don't know how fast you want to go, but a 23 Nova was not designed to go super fast. I'm now running just shy of 700 hp and my Nova is stable/safe/predictable into the low 70's in a 2 foot chop. Any faster and you really need to stay on top of it. Fastest I've had it going is a tad over 83. With some set up work, shortie, labbed prop, bla bla bla, I'm sure it would get to the high 80's with no problem. But to me the hull is not designed such that it's worth sinking the $$ into it to go any faster.

That said, I wouldn't sink a ton of $$ into the engine unless you plan to keep the boat for a while. My 1st mod was taking out the 7.4 and dropping in a ZZ502/502. Boat would do 70 gps any day any time with the ZZ502. Topped out at 73 gps. IMHO it was the perfect engine for the boat.

Hope this helps with your decision.

Good advice, the speed bug has bit us both pretty bad. You are a little further along than me...... :lolhit:

pantera232 07-20-2011 05:50 AM

Ya i put a good 2500-3500 into mine i did alot of the work myself. plus lost track of the money i spent on alot of **** lmao.

Still dont think i have 500 hp, even with 781 heads, .6 lift bob m cam, edlebroc air gap intake, I already had the sm manifolds, and still using my stock 750 holly carb, and oil lines and oil cooler, i only run hard for short bursts, when i see oil pressure fading i let it cool down but going to upgrade lines soon. I even kept stock valves as crazy as that sounds, but that was bc bob m didnt advise me to change those till i had heads assembled even though he was the one to order the harder springs and ship them to my head guy..... which took weeks, the morel hydraulic lifters were a couple hundrend easy, ( I dont know if you really need that expensive parts but..)

Kidnova 07-20-2011 07:57 AM

rmbuilder was huge in parts choice on my 557 build. I bucked him on a couple of parts choices and initial dyno results were ok'ish. Then I caved to his demands and back to the dyno, and we saw a very substantial improvement. We were both happy. I should have listened to Bob from the get go. I also had a terriffic machinist/assembler bolt the beast together. And like Bob, he also knows his schidt and did a fantastic job.

It's not what you know (or what you think you know) it's who you know, and how much $$ you're willing to part with. hp ain't cheap.

95caliber 07-20-2011 12:26 PM

Kid, you on oneida? I have been out of boating for a few years but I use to have a 32 outlaw/caliber that i sold 4 years ago. I just picked up this Nova to get out on the water, and as you know it being left in the dust sucks. I dont want to put $10gs in to the motor, 3-4 grand at most. Maybe it will get me up to 70?

drpete3 07-20-2011 01:46 PM

Just my 2 cents but if you want to go faster sel the boat and buy the boat that is fast enough for you. You will save a lot of money and also down time.....been there done that

95caliber 07-20-2011 04:01 PM


Originally Posted by drpete3 (Post 3457722)
Just my 2 cents but if you want to go faster sel the boat and buy the boat that is fast enough for you. You will save a lot of money and also down time.....been there done that

Ya, You've got a point! I know I wont get back any of the money I spend on the motor. Ive already done that with cars and boats and wasted tens of thousands. Decisions,Decisions:lolhit:

kneeslider74 07-20-2011 10:52 PM


Originally Posted by gsxr1216 (Post 3456283)
??? $2500 that will get you the exahust to support 450-500hp and thats about it, oh maybe some gaskets and a few beers! to install it!!

having just gone this route starting with a 454MAG with 088 heads that didnt get any port work i can tell you to make 500hp you will evaporate ALL of $5000 easily to do it right and make it last by the time you do cam, intake, carb, exhaust, valvetrain components, fuel pump,gaskets,timing set,machine work/replacement parts thats needed to bring your OEM parts back up to snuff, ETC the list goes on and the $$ add up quick!!!

if your looking for a cheaper route and not near 500hp on your build i have the stock 454 MAG aluminum hirise intank and matching carb i took off mine when i upgraded my motor that i'm going to sell.

good luck on your project!

You are right, I did not consider the exhaust, motor buil to me does not mean the dressing.
I see new people come to this site that are new to boating and too many people make this seem like if you don't have a million in the bank you can't enjoy the water or boating, much less own a boat. You simply don't need a ton of money if you are creative with your needs.
And so I don't get chewed by the good guys that are always willing to help, I would bet that if someone asked and had circumstances that they needed help, they could about build one for free.
With a decent block he can do it for 2500. No he cant go about it like the bunch of thick wallets around here, but there is an adbundence of good parts cheap available. With some DIY No problem.
You will have to have a buddy bring the beer! I know that there are some part you can rework and save some money. Yes do it yourself, you will get it done right. For those who think you cant try googling 500 hp 454 and you will find documented builds for less than 2500 starting with nothing, putting out more than 500 hp. IF YOU DO IT YOURSELF. If you are luckey enough to have worked hard and have the funds then great, you don't have to worry if you choose not to DIY. I suppose some of you would also sy he could not buy a 500hp EFI for less than 4k either.
Must be IMS kicking in.
Here is 565 hp and 532 t for $2500
http://www.superchevy.com/technical/...ild/index.html

BTW I have done 3 mild 500's in 3 years Yep they are still going. I last paid a guy to freshen my 2 and on break in they realized a oil line was pinched. So yes I at least know more than them!
LOL,,, quit laughing put the beer down, and pick up a wrench.....:drink:

kneeslider74 07-20-2011 10:57 PM


Originally Posted by Kidnova (Post 3457121)
Just saw this post, and..... yep, and then some LOL

In NY smokes are also $10 a pack and you probably pay to park too. Will have 5 ove 500 by the end of the month. Keep laughing. Proof in the pudding.


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