I have a 454/330 that seems to have lost a head gasket so time to upgrade.
I am looking at a scat forged 496 rotating assembly and for the top the edelbrock marine package, marine performance rpm heads, cam intake and carb. I have emi thunder exhaust but I emagine that will have to be changed out due to the ex ports.
this is about 4k in parts plus exhaust and machine work to the block.

I am new to the marine industry and would appreciate any thoughts/input on going this route.
I am looking for reliability with a bump in horsepower.
Thanks in advance.

I changed my 330 over to a 496 this year. I started with complete eagle forged assembly int balanced. H-bean rods, srp pistons. It runs 9-1 cr with 118cc large oval port heads with 2.25 and 1.88 ferra valves 11/32 stems. I run a custom grind cam with the firing order changed. A DUI ing, RPM air gap intake and a 850cfm deamon carb. I am running revolution exhaust and did so on the 330 engine. It runs pretty good. I started out with a 330 then went to a 420 and now a 496. They tell I am close to 500 hp all I know it runs good

If its a 2 bolt main block, start from scratch or buy a different longblock complete.

Alright before I posted this I used the forum search and found a few threads on this topic. Now that i have posted the thread I scrolled down and took a look at the similar threads, I am now totally lost and had no idea that there were so many options and combinations for the 496. Right now I think my best bet is to scrap the 330 and purchase an engine from a reputable builder.

Just curious if you upgraded to a hydraulic roller cam and lifters or if you stayed with a hydraulic flat tappet...??? Also, did you stay with the stock GM oval port head castings---"049"? That is an interesting project---my cousin may be doing the same type of upgrade to the 496 from his Mark-4 Merc 330 blocks.

No I stayed with my four bolt Gen V block, I went with a Eagle rotating assembly h-beam rods, SRP pistons 9-1cr. I have my stock 330 heads but I switched them out to large oval ports, ported and flowed with 2.25/1.88 ferra valves with 11/32 stems. I running a air-gap rpm intake, 850 sea demon carb, DUI ign system, revolution marine exhaust, k&n filter, -12 oil lines with a K&N 5001 filter high volume oil pump, running a flat tappet custom grind cam with the 4-7 swap on the firing order and crane gold race rockers. I personally feel the cam is too small. The boat runs really good and is on the verge of chine walking sometimes. I think I am going to leave it alone, but I will say this it sounds a little different with the cam and my wife and friends don't like the way it sounds.

Here, Save some time money and effort. These will work with your exhaust.

http://cgi.ebay.com/ebaymotors/ws/eB...3AIT&viewitem=

That looks pretty similar to my bottom end but I am running ARP studs and a windage tray

Not making enough power or turning enough RPM/s for studs. I put the Merc trays back in.

Just run of the mill Eagle rotating assembly with the bolt upgrade.

My windage tray wouldn't clear the throws so i had to go with studs. As much money as I have tied up in this thing I should of just bought a 502 I think it would of been cheaper. Because the price I was quoted on my head job was way low. I also had machining done to the lifter bores to increase oiling. I love the low and midrange punch, my wife was asking me the other night if I could do something with the way it sounds so i might just install a larger cam