Cam swap
 

I just acquired a Baja 272 with a 454 blower motor. I know nothing about the engine but what I can tell is it has a weiand 177 blower. The cam sounds like it’s a little bit more than standard but it certainly is not crazy. It has a 4150 Holley carb double pumper. Rockers are stock. I don’t kNow about the Springs.I want to get this motor to have a high rpm at idle With that ratty tat exhaust. Not the lopey sound. It was suggested to me to use the crane cam 168741 but it has a lobe separation of 112degree. To me it doesn’t seem like it would give me what I wanted. Don’t ask me why I want it, I just want it. I don’t usually drive over 30 or 35 miles an hour if that’s any help. I have the bravo one outdrive. It gives me goosebumps when I hear a boat motor that has a fast title and a ratty sound. Not knowing as much about camshaft I would like to hear what you guys have to say and any other recommendations. If the cam 168741 from crane is what I want, then let me know because I’m driving myself crazy.Thanks

So, if it has cast pistons/oval port heads/a crappy exhaust, that foesn’t matter when picking a cam ?

Very good boat choice btw. Uktimate oerformance, no, but a great boat all around. :thunbs

Not to try and sway you but a bad cam is an easy way to make a fast boat slow .
check the thumper series cams from comp.

Thanks SB it’s just a cool boat to mess around with.
thanks car nuts X2. I know about the thumper but thumper is basically made just for the sound and Performance cut down. Right now I’m in the midst of trying to keep the power up and get that sound that I want because with the changing exhaust that’s going to help, the blower is going to help. If I can maintain that power and get my sound have a high rpm and that ratty tone, i’d be as happy as a man with a glass of wine sitting on top of the space needle. Trying to compromise all that is tricky but that’s why I don’t know if that MerCruiser525 race cam is going to do the trick as I mentioned the lobe separation being 112°. if they’re going to be wrong I want to make sure I know it

That fast idle that goes along with the aggressive camshaft will bang your drive apart going in gear and make the boat a pain to drive around docks/marinas/trailer loading. You got a blower motor sleeper, go dust some people and have fun.

Most of the bad ass sounding boat's have a well though out engine plan. They just don't throw a cam in them.

What exhaust does it have?

your gonna need a 3/4 race cam to get that sick sounding bravo busting sound.

Hi liberator, from what I gather the RPM really isn’t that high but it’s more of the sound in the exhaust that gives it that feeling. I have a brother one and right now the RPMs are at 800.No jerking just nice smooth transition into gear but I know what you’re saying.

Hey Payton, I’m changing from the stock exhaust to the Eddie manifold and stainless riser exhaust. I previously removed the baffles and added corsa tips. I was thinking over the evening that maybe because there is a slightly beefed up Cam that changing to this Eddie exhaust system may be enough to satisfy me but I doubt it. I have had many jet boats with Bassett exhaust and boy did we plan those engines out. I don’t know if it’s possible to do what I want with what I have and I would rather not have to go into the expense of redoing that whole engine. Thumper cam is good for that but it’s also not good for power but then again my days of racing boats are over and I just putting around like a little 74 year old not going over 50. So there’s other things to think about.

Hi Sutphen, My question is what constitutes a 3/4 race cam. Things have changed since the 1960s when I knew what a three-quarter race cam was but that’s progress. My question is is the camshaft from a 525 MerCruiser going to give me what I need or what I want. That’s what I don’t know. Among other things

Not to throw shade on myself or my offshoreonly.com brothers and sisters but call the experts at Comp Cam, Clay Smith or Brian Tooley Racing and see what they recommend. Unless you really like swapping cams I'd want to get it right the first go round. My guess is their response will be WTF. On a side note you could just add fuel injection and program the idle instability into the programming.

Thank you

Swapping to a new/upgraded hyd roller cam requires a lot more than just a cam. You'll have $3k into this swap to do it right.

Thanks Griff. Between the cylinder head porting roller rockers and lifters ,exhaust changed to , I got it I’ve had a number of engines built for me even one for my cobra which is a 427 550 horse but this time being lazy I’m being told that the cam swap to a crane cam 168741 would do almost as good without having to do everything. The engine only has 32 hours on a rebuild at which time he put in a little wild or Kim and a 177 blower. But I have no idea what else he’s done which would require a total rip down of the motor to find out I was thinking about a mother thumper or a big mother thumper. This mechanic wants to put the crane cam 168741 in saying that it’ll give me what I want but I just don’t think so. Thanks for the reply

Dry exhaust.

Mother Thumper cam with a supercharger ? Lol

Mother Thumper Cam with typical marine exhaust ? Lol

Mother Thumper Cam 800rpm to shift in/out a Bravo ? Lol

Let me be a guy with a little reality here by saying Lol.

Im not and engine builder nor do i play one on tv... but a blower gives surge at idle and isnt making boost at idle .. if you want raspy.. ditch the belt driven intake manifold jack the compression up and dry pipes. Or get an mp3 of a top fuel dragster and a really loud stereo

Get a Cam that performs and works with your setup ....

Who really cares about what it sounds like if it is not right, not reliable, or blows the drive apart from a stupid high idle.

I knew they’d be an idiot somewhere. Reality is not your cup of tea, SB!lol

I’m truly sorry that I asked anyone here for any advice. I’m really not the type of person to have to defend myself for asking a question or explaining my 800 RPM which three mechanicsSet. Nor will I answer A goofball about an MP3 player and a surge answer When there is no surge at idle with a 177 blower.. But I thank the other ones that had some knowledge of what they’re talking about.
Phragle,your right,your not an engine builder. To the other people especially in the beginning of my question, thank you for being professional. Sorry again for asking a question. Ciao

You came here asking for answers and opinions.

Blame a guy for being honest ?

Same theme, you are trying to push people to answer what you want.

LOL is not on the floor rolling and laughing.

I speak in round table talk.You don't know that yet. That;s fine.

Oh well.

Yes, I am an idiot and sometimes called a deplorable. I am dirty 90% of my day. I smell like walmart too. I am fine with that. Lol:)

Just so others know, that aren't familiar with the mutha thunper cams, they are typically cut with a 107 LSA and have 13-14 more degrees exhaust degrees than intake.

Here is one xample: https://www.summitracing.com/parts/c...make/chevrolet

This, with more duration than needed, is what give these cams the rough idle.

Unless you want to spin your engine to 5800rpms, that cam is too big for a marine 454.
The nearly ideal cam for what you have is 168731. BTW-Crane Cams is GONE.
You've got basically a 525SC Clone. If you want to do some real research, do an advanced search with 525SC and my screen name. You'll see numerous threads and posts from several knowledgeable people. Ask your "mechanic" how many of these types of marine builds he has actually done.

Thanks Griff. You have answered my questions. This is what I was trying to get to. I had no idea crane cams was gone . I will do as you ask and learn from it .again thanks so much

Yep. I must be hallucinating.. my 454 with a 177 dynoed over 650, runs great in the boat and sounds nice. 731 cam btw..

BUT does it have a high, raspy, " ratty tat" idle ? 🤣

Put a stock Mercruiser cam back in and call it a day.
Esp if 35 mph is your goal ....
My bone stock 454 does that at 3k rpm in my Baja 252.
Have you driven your 272 yet?

3/4 cams are for posers. ALWAYS go full race.

Need to be VERY careful with those kind of LSA and exhaust duration in a marine application. It can cause significant mullet reversion when admiring the idle from behind at the dock. Not even aqua net will hold up.

Yes CT

had a guy at a car show ask me once if I had a 3/4 cam in my 442, I said "no I put the whole cam in it". he didnt talk to me anymore.

Lmao

I had a guy get a car so talk to me That he couldn’t get the lift out of his cam so I told him to use a jack

I had a guy get mad at me when I fold him a mutha thumper cam wouldn’t wouldn’t work in his boat. :wink :)

Sound clip for you....

Good , at least you have a baseline then if you do swap cams looking for your sound goal.

Honestly not trying to give you a hard time and dont think others are either...

I just enjoy boating too much to see someone spend time and money on something that might not help them one bit for the sake of sound.

I had a Cam in my WS6 Trans Am that made the car almost undriveable for the average person. Made great power and had a nasty idle , but it was a chore to drive. Personally wouldnt want that on a boat. Gotta keep them Baja's on the water !

JesusPhragle, you just jumpstarted my heart. I think I’m learning a lesson with all the reading and the help from others that this just isn’t gonna work. It looks like the only options unless again I’m mistaken that won’t mess up my power and will increase my horsepower without damage in the engine and not having to do $3000 worth of change to it will be that crane cam 168731. To be completely honest, when I start that boat I want peoples heads to turn. I know it’s not the right reason but it’s my reason. It would be the only solution to gain power in a 454 that’s mildly changed. I am just addicted to What sounds like a dragster on the water and a wild sound that comes from a builtup motor. I just can’t get away from that wild and crazy sound of a hot cam. Just didn’t know a lot about putting a motor together on the boat. It was always done for me. Thanks for your advice everybody if I’m wrong about that crane Cam which I know is made by someone else then just tell me and I will drop it Like a hot potato and just go with my new exhaust. Thanks again CT

but you don't have a full meltdowned daughter watching the 3/4 race cam go by.:D