If not for bad luck I'd have none....finally got boat working and Big block goes boom

Well if you want to add knowledge you going to have to prove it. Build your motor, put on your stock exhaust and dyno it. Would love to see the results. Not sure why you got an attitude.
Because you started talking shit out of nowhere
 
Tell me what the shit part was? I might be rudely honest, but talking shit isn't what I do.
 
Now you are just totally making things up. No ify pitched in ANYTHING of specific substance for the rebuild so I spent weeks doing additional research on my own.
I know the motor has reversion issues. Everyone keeps saying that but guess what? Nobody has presented a single solution!!!! As for you proclaiming that I'm putting in a larger duration cam inspire of it like I'm a total dumbass is totally false. Obviously my internet research has made me far more knowledgeable on this topic than many.

So for those that find this thread in the future while researching similar issues let the record show the following:
Merceuiser had 2 different gm based 454 engines. One was called the "7.4L Performance tuned" and the other was known as the "454 Magnum". The 7.4L had a rating of 330 HP while the rating of the Magnum was 385hp. If you look at the cam specs from the Magnum you will see that it is nearly identical to the comp cams marine cam. So no, im not putting some wild and crazy cam in when I know there are reversion problems.

Last and certainly not least, REVERSION DUE TO CAM OVERLAP IS NOT THE ONLY ISSUE EITH THIS MOTOR AND IS ARGUABLY THE MORE MINOR ISSUE! The bigger issue is the lack of a vaccumn break that allows the exhaust pulse waves to make the water revert. We are talking minor drips of water that are allowed to drip into the cylinder. A proper vaccumn break cast onto the riser would resolve this issue without obstructing the exhaust. Turbulator plates are a solution that allows the drips to land on the hot turbulator plate and immediately turn to steam but again it causes a huge obstruction. The other workaround this is to try to avoid idling as much as possible and prior to shut down run the motor above 1500rpm for a 60-90 seconds and then shut motor down.

I'm so sick and tired of ignorant old school gesr heads rejecting science and facts but.obviousky that's the world we live in today. You go online and find a million old school gear heads swear up and down that "Peanut head ports can't make any power" "peanut port heads are terrible" and it's all based off some.shit they h are from somewhere or their butt dyno. Then Richard Holdener comes along and literally gives the step by step along with dyno runs to support it and people still refuse to believe it!!!!

I should really fuck with you guys and throw some aluminum heads on this thing and take the horsepower up over 600!!!!!!
"totally making things up"
"ignorant old school gear heads"
I'll say you don't know me nor anything about me. So, those statements are a reach. I'm only trying to help as are others. I think you went a bit in the wrong direction; you believe differently. That's fair but you don't need to be so arrogant and foul about it. First you put forged pistons in an engine that runs cold all of the time; you will pay in early loss of cylinder pressure - that's my experience talking; I've been down that road. Secondly, that boat squats and takes quite a backwash when coming off plane and the exhaust risers are under the water level with the engine at idle; it will take in water - that's experience talking but you think something about a vacuum break is the cause...
Now you are saying that bolting on a set of aluminum heads will make a magical leap to 600 HP; sheesh..
So you know a bit more about where I'm coming from:
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Oh ya pricey, thought you had money to burn? Freeing up exhaust flow is the first thing a gear-head does. right? So if your reversion continues you'll have to go to plan B
This post seemed to have a healthy dose of sarcasm and smartassedness in it. My apologies if that wasn't your intent and I misinterpreted it
 
"totally making things up"
"ignorant old school gear heads"
I'll say you don't know me nor anything about me. So, those statements are a reach. I'm only trying to help as are others. I think you went a bit in the wrong direction; you believe differently. That's fair but you don't need to be so arrogant and foul about it. First you put forged pistons in an engine that runs cold all of the time; you will pay in early loss of cylinder pressure - that's my experience talking; I've been down that road. Secondly, that boat squats and takes quite a backwash when coming off plane and the exhaust risers are under the water level with the engine at idle; it will take in water - that's experience talking but you think something about a vacuum break is the cause...
Now you are saying that bolting on a set of aluminum heads will make a magical leap to 600 HP; sheesh..
So you know a bit more about where I'm coming from:
View attachment 116334 View attachment 116335
so guess what, if the problem with forged pistons is that they expand when they heat up but now i have an engine that you say doesn't run hot than I guess I don't have a problem with them expanding either? which is it?
2. you clearly have no idea what a sea ray 260 sundancer is if you think the exhaust risers are below water level when engine is at idle. We measured., There is 20 inches from water line to the top of risers without spacers. Mercruiser spec is for 13". Because of the notoriety of reversion issues, we are going to install 3 inch spacers which is the max we can go and still get the engine hatch to close. Also, there are brand new flappers in my y pipe so coming off of plane should be zero issue and obviously a good captain can take care to slowly come off plane in most instances and make water coming hard into the stern a non issue. You say i'm talking shit about a lack of a vaccumn break being an issue? guess what pal, I found the link to the SCIENTIFIC study done by an ENGINEER. I will be posting it as soon as i figure out how to post the pdf.
And lastly, you should go back and watch the Richard holdener video i posted because the very last dyno run is him taking off the peanut ports and putting on aluminum heads and taking the 454 up over 600HP but yeah, you strike me as someone that doesnt believe in science. You can talk shit about me all you want. Intelligent people that can read and comprehend will see that i'm asking questions on things I don't know and the things I do know I have no problem citing sources for their basis. What the hell is so hard about this?????
 
Novice to expert with some youtube vids. Funny. " guess what pal" ?? shit talk like that gets you nothing.

I'm sure TT has forgotten more about engines than you'll ever learn.

TT I'm sure your running peanut ports on that rig. LOL.

Wet man why not just lighten up? You might just learn something. Anyways got a good chuckle out of your posts
 
If you don't believe in science, don't waste your time reading the below pdf. Basically everyone talks about reversion due to cam overlap with 454s but the neglect to understand the issue of "Resonance Reversion" The nuts and bolts of the below document is that risers USED to be made with a vaccumn break in them that prevented the water that was backing up from making it all the way back into the cylinders. IT seems like it would be something really easy to engineer back into a modern casting and make a fortune but nobody has done it.
 

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Freaking wicked! Did you build that intercooler yourself?
I ran a boat in the IHBA years ago then moved from Ca to Fl and had no use for the comp boat and sold it before the move. I built this little squirt boat for the river here to get my "fix". That was an old TR2X tunnel ram I had in the attic I cut off the top and put the IC box atop. That was a fun project and really fun boat but it's now gone to someone running it on the Swanee river. I'm on to the next build with the 597 turbocharged hemi in the first pic.
I've always wanted to run the jet sprints and white water in your neck of the woods. Bucket List for sure....
 
Novice to expert with some youtube vids. Funny. " guess what pal" ?? shit talk like that gets you nothing.

I'm sure TT has forgotten more about engines than you'll ever learn.

TT I'm sure your running peanut ports on that rig. LOL.

Wet man why not just lighten up? You might just learn something. Anyways got a good chuckle out of your posts
Its very obvious to me that he has forgotton a lot of things.

I don't need to lighten up. I'm good. I just don't understand where the snide shit talk came from. I had pirate lady ask what I thought was a reasonable question and when I gave my very reasonable answer it was apparently such a surprise that I received snide remarks. then it continued on with you and with TT. IF you guys don't want to help, thats fine. Again, I am well past the point of needing help anyways, the motor is done. It's going in this week. We will find out next week how well I did.
 
I totally agree with you, you have all the answers. Why bother post again? I'm sure it will be perfect and everything you were looking for, might as well start patting yourself on the back now. Why wait? Don't forget to thank youtube guy.
 
I totally agree with you, you have all the answers. Why bother post again? I'm sure it will be perfect and everything you were looking for, might as well start patting yourself on the back now. Why wait? Don't forget to thank youtube guy.
i certainly don't have all the answers but why should i listen to a guy that comes on here and talks shit to me and then makes multiple silly statements that are easily disproven. Statements like Forged pistons are bad. Really, thats funny because mercury certainly used plenty of them in 454 Mag motors over the years! or statements like worrying about vaccum break is silly and then be shown a research paper proving they are important. Have a nice day guys. I'm confident history will be kind to my posts and show someone trying to add some clarification where there is so much lacking.
The bottom line is there are so many different versions and iterations of these 454 cubic inch motors. You have carb versions, Throttle body fuel injected, multi-point fuel injected, forged internals, cast internals, rectangle port heads, peanut port heads, so on and so forth. I'm choosing to rely on documented information with dyno charts and parts lists by well known reputable professionals. I think I'll be fine.
 
I've always wanted to run the jet sprints and white water in your neck of the woods. Bucket List for sure....
Funny thing; when I saw that picture, the first thing that came to my mind was "Through a roll cage on that thing, and bring it up to Idaho!"
 
Funny thing; when I saw that picture, the first thing that came to my mind was "Through a roll cage on that thing, and bring it up to Idaho!"
Brings back memories going through the pics... I miss it in many ways; it had a "presence" and was flat fun to run at tune. Although, after an hour or so you needed to stop and unravel.
DSC00367.JPG
 
Wetman, i am enjoying the build, really am, but slow down, you’re tripping over you feet. I make a comment about watching fuel cost, you say I shouldn’t own a boat if concerned about fuel, then you say this. but the rich don't get rich by throwing money away right?
So what is it, you got money to burn or you get rich watching your money. Slow down, nobody knocking it in the dirt.
Keep up the progress reports and good luck.
 
All good pirate lady, you already acknowledged being a bit out of line, it's all good. I'm pretty sure I never said I had money to burn. I value my money and I have plenty of it to spend, I just don't like to do so foolishly. In my opinion, I was able to get over 100hp gains vs stock by only spending an extra $300 or so. That's great bang for the buck.

If this works out well I am going to the junkyard and buying every 454 I can find and opening up a shop because I got this done for way less than. All of the online outfits. The reason they give 3 yr warranty's from Michigan Motors is because they charge 3x as much as the rebuild costs! Lol
 
How did I miss this thread?

I love hearing how people ignore sound advice, blow things up and then blame the people who are trying to help them.;) Pretty bold to take on @ttmott, @techmitch and @scoflaw and throw insults their way. I may not always agree with them but I would trust them without hesitation if I needed advice on an engine build.....no better bunch of gearheads.
 

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