I have a few questions here:

How much can the stock rotating assembly in the block take? If I wanted to do headers, heads, intake, carb, cam, valvetrain etc...

How much can I reliably expect the cast rotating assembly to handle all day long?

Option #2

Replace the cast rotating assembly with a forged assembly, and continue with my build.

I am not looking to go crazy with the motor, but I want to get a little more punch out of it.

Maybe 500-550hp range...

Thanks in advance!


As stated before in another thread I had started. I am a master auto technician, but that is completely different from marine as I am learning. So in a car I would take a stock big block to 500hp all day long, but as for marine, I dont have the experience of what works and what doesn't to the kind of load these things are put through.

I am going to build the motor myself, I am confident in my skills. I have about 15 or so sub 9 second race motors under my belt without a failure... few 6+ years old and still spankin down the track.

If you are planning on 500 HP you will need to bore & stroke it to 489 or 496. Looks like you are prepared for exhaust, be sure you get long risers. Your will need to upgrade the oil system, filter pad, lines, oil cooler. I use large oval 820 heads. For that kind of HP you will have to go roller. I just went through that that will cost about 2k just for that. I used RM Builder for my valvetrain design, he really knows his cams. There are a lot of things that you do not think about that really add up. Check out my thread on Roller Cam Upgrade. I just went through the lower end about 60 Hrs ago so that part was in good shape.

It depends on what block u have ,,,if its a 4 bolt main the 500 is fine ,,if not ,,,i would not waist my time.
Now some maybe tell u since its a 330 its a 2 bolt main ,,but i seen 4 bolt main blocks in 330's .So thats not always the fact.

I have a stock Gen-V 330 horse engine. I put a 177 Blower on it. It has the stock everything....cast piston cast crank small pushrods oval heads. This is my 4th year with the boat and I have never had a problem with it. I'm running 5-6 lbs of boost and suspect around 500 HP. It sees boost for 20 minutes at a time and holds up. I keep the timing at 28 total to be on the safe side.

He is right, check and see if it is 4 bolt main. Mine was a Gen V 330 and is was a 4 bolt. From what I have heard most marine BB use 4 bolt.

Another question... is the 330hp rated at the crank or propshaft?

Depends on the year, Gen V at crank, Gen VI at prop. I am pretty sure that is when they changed. Gen VI would have come out in 1996.

Check out the thread on oiling system. It was just brought to the top. This is how I found out about how to upgrade my system. I did this after blowing the engine up a few times.

check the thread 454 on roids

I ran twin 330's in a 93, 28ft Challenger with your basic upgrades such as Dart oval port heads, Performer RPM intakes, Holley 800 CFM Carbs with the Crane 134561 Cams "502/465 Cams" 3/8 ARP Rod bolts. I ran it extremely hard every time out and never had any issues what so ever. Very reliable package. Never ran much over 5,500 RPM's. I ran the boat for over 4 yrs before selling it. The torque was near 500fps and the HP was 488 at 5,600 on the dyno at More Power Racing in Comstock Park, MI. If you would like the dyno sheet let me know and I'll emial it to you. One thing you'll for sure want to do regardless of what route you go is have your rotating assm. balance by a shop you know and trust. I am a firm believer that is the key to your long term investment and fun.

John

With the kind of torque and HP your looking at both the cast crank and 2 bolt main will be fine. Certainly if you have the extra money to spend put all the good guy parts in your bottom end.