What would be the best cam?
 

I'm just wondering what cam would be best for my 330hp mercruiser 454 bbc with twin 60mm M&W rayjay water cooled turbos in an 1988 Chris craft 245 limited I want it to sound absolutely nasty. But minimal overlap so it doesn't suck water back in. All suggestions are appreciated!

Good luck with that! Go dry and go crazy otherwise your limited to the 741 or similar.

Yes. NastEEEEEE :)
lol. Just makin fun. :wink

The E’s in Nasty is the overlap which csuses the rough idle and the reversion.

I say calm your pants and give the engine whst it wants. It’s a bbc, will have some blurb (looe noise) anyway.

btw: the exhaust wheel on the turbo kinda dampens the noise and pulses.

There's gotta be something that sounds choppy with little overlap atleast a slight bit better with thru hulls right off the turbos even the slightest change should be noticed?

:party-smiley-004:

Uhmmmmm I suggest a bit of research on your part... Twin turbos on a 330 and you want it to sound nasty.... Your followup post will be "why does my boat run like chit"

The cam is dictated by compression and heads amongst other things. The 330 has anemic heads. It also has little rods and a cast crank. Not the best for any kind of boost. Its also a motor that in stock trim is done at 4700 rpm. Turbos like rpm, the rest of your motor doesnt.

Not trying to rain on your parade... but for it to work well, the parts need to match. That nasty sound is the side effect of certain parts working together. Your current concept is missing some key parts.

Like Getrdunn said, dry exhaust will sound pretty crazy to most and sound pretty good with a 731 or 741 cam. The problem is that those cams really start coming to life about the time the rest of your motor is done.

From what I seen opening the motor up a bit it does have some serious work done to it I bought it as a complete set up running from another race boat so I'd assume that all performance parts needed to handle the turbos were replaced but I do appreciate the information I'm new to this and will learn.

Well I appreciate the input guy there's not much I can do but I guess re gasket everything freshen the whole thing up top to bottom and do the same to the outdive aswell and just run it the way it came till problems start

No raceboat would have a 330 hp 454. you need to figure out what you have.. What crank? Rods? Block? solid or roller cam? heads ? etc......

I will tear down into it and have some pictures like I said im just getting into this saw the boat and the engine set up kinda fell in love and needed to try to put the puzzle together.

https://cimg6.ibsrv.net/gimg/www.off...cf2be3d2ef.jpg
https://cimg7.ibsrv.net/gimg/www.off...fe5bb73f0.jpeg

yeah,there is,,get rid of the turbos,,they act like mufflers.

Two pages and nobody’s pitched a cam from Bob ?;)

easy there or else black SUV's will be pulling up to take away your computer

https://cimg7.ibsrv.net/gimg/www.off...4d0fc58ff4.jpg

You don't want a "choppy" cam in a low compression turbo 454 with cast components. The cam dictates the Rev range where the motor is most efficient at making torque. Your cast motor should be kept below 4900-5000 rpm.
We also have no idea how well the turbos will spool up with a cam that has a torque peak way faster than your "planing rpm".

If somebody ran it like it is, then start there.
You really shouldn't jump so far ahead of yourself.
Besides, you need to creep up on speed with your new hull..

Find the casting numbers on your pistons and send photos.. Find the casting numbers on your heads. Find the stamped number's on the face of your cam. Those are good starting info we need in order to help you..

Much appreciated once I get time to tear into it for maintenance before slapping it in for summer il get all photos and info

Now that’s funny! 😂

Ass u ming the engine is truly a 330hp 454 base, and me having 0 turbo exoerience, i would put this one on a list of considerations:
https://www.summitracing.com/parts/s...make/chevrolet

Nope I’d get this. Why?
https://www.compcams.com/pub/media/w...HR-14(LS1).wav

Cause it sounds good!!!

I agree,...also, I don't know if it has been mentioned yet, but a Merc 454cid 330hp engine come stock with oval port heads---the earlier heads usually had the "049" castings and the later Merc 330's had the "peanut port" designed heads, therefore, if you try sticking a bigger cam in the Merc 330, then it will most likely fall on its face and become a dud---plus other issues like valve guide height clearances with the spring retainers, etc, You might..be able to at least get away with a very slight upgrade with perhaps a roller cam, but not much---you need to really do your homework. If you are looking for more power, then I would suggest doing some bowl-port/short-side radius work on the heads, and upgrade to a hydraulic roller if it can be done on a Merc 330, but any cam upgrade will be super limited. Check with a reliable marine engine builder that is familiar with Merc BBC stuff....especially the old 330.

In addition to what I have already stated above (I forgot to mention)....Just keep in mind that the Merc 330 usually came with an all cast rotating assembly and only a 2-bolt main block and now somebody has added turbos---yeah?---I really would not do too much more than what you already have there...just my .02 Mark