Just purchased my first boat for a restoration project since I just finished restoring my 1976 280z. Had fun building up the car and thought maybe it was time to learn something new so I bought a boat.

I have already pulled the motor and it is at the machine shop. My goal is to get as close as I can to 400hp but anything over 330hp is fine.

So far purchased/plans for the motor:

22cc dome speed-pro pistons .030 over (should be around 9.3 to 9.4:1)
120cc Peanut port heads (slight port and bowl work being done by machinest)
Edlebrock Performer intake manifold
Stock mercruiser exhaust
Rotating Assembly fully balanced

Only thing I have not decided on is the cam selection. What cam profile would be best for my build?

I read of someone on here running the isky 270/280 mega (221/232 @.050 on 114 LSA) with the stock exhaust and no reversion...

May also go with 049 heads over ported peanut heads which would lower the compression even more.

Personally I would read up on a thread here "330 on roids" before proceeding any further. The vortec L-29 heads would likely be your best bet if you want to retain the factory flat top pistons** EDIT: didn't see you plan on using domed pistons! At any rate, I did quite a bit of research regarding this topic. I bought a low time set of L-29 heads before deciding to scrap the project in favor of a 496. That said, you can still get really good performance(solid 400hp) from peanut ports with stock sized valves. You just need a good cam and exhaust with your other planned mods. I would upgrade rod bolts at minimum. Don't take that as the 330 isn't worth upgrading, because it is to a point. You just have to approach it with reasonable expectations.

Don't listen to all the rich guys here who will automatically recommend you toss it in the corner of your garage for a built 540...... They don't understand that we all aren't made of money and if we happen to be, don't see the point of a $10,000 motor in a boat we will likely sell for another in a couple years.

There are however some very experienced, friendly people here who can get you steered down the right path. Best of luck on your project!

Thank you. From my searching I have seen both of the people you speak of on this forum.

I don't necessarily need 400hp but the motor needed to be rebuilt and I hate going back completely stock when I know there are some things I can do to give her more pep without breaking the wallet.

I would really like to keep the stock exhaust for now as that is the most expensive upgrade for this motor. I was just hoping to raise the compression (I will be running premium 93 octane at all times) put in a mild cam do some port work on the peanuts so that I could retain a ton of torque. Supposedly the peanuts with a mild port can do about 415hp and over 500 torque from what I have seen. The only reason I would swap to the 049 heads would be to lower the compression a little bit as I fear it may be a little too high.

So in short what would be a good cam to use while retaining the stock exhaust with the above mods?

Longhorn- There may be some people selling using HP 500 intakes and carbs- these are well worth it if they arenty asking too much. A 454 with a good roller cam HP 500 intake and carb will make 400 hp no problem if the heads are worked on a bit.

I have Merc 400's (454) that have been bored 60 over has CMI headers- Iron eagle heads and roller cam, HP 500 intakes and 800 cfm Holley- MSD ignitions- dyno 475 hp each.

EDIT: Member Rbesola has HP 500 intake and carbs.

Check the other threads in this section. BTW exhaust will be your limiting factor very quickly as the factory merc manifolds are really only good to about 370 hp. and reversion is an issue if you put much more lift and duration increased.

GOOD LUCK

Wannabe

So basically if I keep the stock manifolds I should just go back with the stock cam and stick with just the ported peanut heads and increased compression for my boost in power probably 350 hp.

BTW please stop recommending things I do not need. My final goal is about 400 hp which can easily be made with the peanut heads along with gobs of torque. I only have a bravo 1 drive so no need to go over 400 hp or I will be breaking things I cannot afford. The quadrajet is a great carb and will do just fine if tuned properly so no need for a different carb. Also I don't need to spend 1200 dollars on a roller cam setup (especially if mercury can make 400hp on a flat tappet)
Also doesn't the 400 hp 454 have the same log manifolds as the 330hp if so your 370hp rating on the logs is completely wrong.

If you want a good cam go with the 454 Mag roller it's specs are as follows:
483/483 lift 224/224 duration w/115 LSA.

I wouldn't say 400hp can be easily made. I highly doubt you will see 500ft pounds. Actually I'm very confident you won't. I contemplated doing something similar to mine as mentioned above, and after researching a bit, learned quite a bit. Mercruisers numbers are a little off at times. The blue motors are underrated though. It's too bad boat HP doesn't come as easily/inexpensively as with a street setup. I would have a 1000hp boat if that were the case!

http://www.offshoreonly.com/forums/g...h-power-2.html

Here is a peanut making 422hp/500tq

Longhorn- You definitely want an upgraded cam, springs and new lifters. Don't go crazy but whatever RMBuilder suggests.

Wannabe