I had an engine come to me once for a rebuild.  I was not the original builder.   When I put it back together I checked and found the timing mark (notch in the timing cover) was 6 degrees advanced.  Guess that explained the holes in two pistons (it was a blown engine)

Ok, My new to me 78 Mariah Jet has a 468 inch Chevy with a 6/71. I've been having a backfiring issue I thought was ignition related. The previous owner left the distributor (Vertex Magneto) a little loose. Timing kinda crept waaaay up on me before I figured that out. Finally did a compression test and found two cylinders with 0 compression! I'll be taking it apart over the next few days - I'll report back. Ouch!
Ralph

Want to bet on burned pistons if the timing got too far advanced?  Hope it's not two adjacent cylinders,, that could be ugly if the block and/or heads got burned.

It seems like most jet boats I see for sale have a big block.  Why is that?  I see a lot of "Olds 455" jet boats on craigslist by comparison say a ford 460 or chevy 454. 

Is a Chevy 454 a good motor for a jet boat?  I had a 350 small block in mind, but I would rather not get it all setup and then wish I had a big block.

I am looking to build a motor myself, it will be my third V8 and I want to make a motor that has a real snappy throttle response that sounds good but is not too loud. 

I won't be racing the boat. It is just an island cruiser that will hopefully gather a crowd.  There are not a lot of wicked boats around here any more because the sheriff tends to ticket speeders and noise.

Thanks again for your help

If you don't have any mounts or accessories for the boat to begin with, you will find that big block Chevy mounts and exhaust are the easiest to find

If you think about a basic, mild performance build that may yield around one horsepower per cubic inch, the logic of going with a 454 big block vs a 350 cubic inch small block is obvious, roughly 100 horsepower difference. 

"Noise" of the engine will be more related to the type of exhaust you run, although variations in displacement and compression will make distinct differences in the sound of the engine.

First of all, I would not agree about that Jeg's "marine" engine being ideal for marine use.  Note that it has a cast crank, factory rods and hypereutectic pistons.   I normally would highly recommend forged components.

Marine engines have to be looked at differently than "street" engines for several reasons.  They run under a constant load,, no "coasting" at all,, let off the pedal the the boat stops moving.  Also, they routinely run about twice the rpm of a street vehicle.  My Chevy truck runs about 80 mph at 2500 RPM.  Depending on the particular boat and drive,,  2500 may be barely planing, and constant running RPM of 4000-5000 rpm may not be uncommon.

Due to the above mentioned facts about marine engines, and also the difference in block temperature between a street vehicle with a radiator that runs perhaps 180-200 degrees all the time, and a marine engine that may never reach those temperatures, piston to wall clearance is usually (always in anything I build) increased since the block is cooler(less expansion), and the pistons are hotter(more expansion).  Along with that, engine bearing clearances are typically "looser" for the extended higher rpm running and loads. 

cool thx let me  from what i know the 366 is a tall deck and can be bored to fit the 427 pistons with no problem again thank you

Better check carefully about maximum bore on the 366, I have not heard of that being done.  Doesn't mean it's not possible, just make sure before you spend money on a 366 block.

my wife wants to learn how to water ski so i need to get some ski's. i would like to know what kind to get? i have looked at some ski's and i see the really wide ones wich to me would be easy for her to get up on?  she is 50 years old so this has to be pretty easy for her to do or she will just say forget it... i really need this to be enjoyable (?) for her if we could get a set that would work for both of us that would be a plus and im 240lbs.

i have seen o'brian connley and other brands but am not sure how long they should be and so forth. what say you???

thanks ralph

Hey Ralph

Ideally you both want to get to one ski as soon as possible,, easier to control, easier on the back, etc.  You may both want to start on doubles, unless one or both of you is particularly coordinated or used to other "balance" sports. 

It's going to help a bunch if you have a good driver when you are learning, good observer won't hurt either.  Depending on where and when you plan on trying, I would be up for helping.  I am 5 minutes from Puddingstone, got an outboard ski boat that's tough enough to get me up wrapped up.  (Don't know if you are aware of my ski racing background?)

I have some carbs here, 850 double pump,, or 750 vacuum secondary, even a Barry Grant 825 with the interchangeable venturi.

Who in socal do you guys use to do your re-chroming? I know for coating embee is the man but what about plating?

I think my polisher in Baldwin Park get get them chromed.  He used to have a plating business until regulations forced him to close.  He takes good care of my stuff.

Where?

I am in Glendora (So Cal),, maybe not so handy for you.

I have made a deal with my polisher to build an engine for his panel delivery truck in trade for polishing labor. 

Therefore,, if you need something polished I would be happy to get it done for you at "cost". 

In the past I have trusted him with some very expensive parts, and he has not let me down.  I am in the middle of finishing up a polished all aluminum 621 cubic inch engine and he did the block, heads, dry sump pan, and Milodon gear drive, but all of that was completed prior to our current trade arrangement.

thanks for the tip. i havent used it yet so its gunna be a learning experience.

If you want more help,, PM for my phone number. 

You will want the valve covers off,, and if you have a deadblow or rubber mallet it can be helpful.

So the new I just built las season seems to ave quite a bit of blow-by. Its a 468bbc,990 heads, Not positive on comp ratio. SLR cam, 500 lift. MSD ign. Wieand team G intake, holley 850.
I've got oil coming out of my breathers, I am going to setup a puke tank, but what can I do to not hide the problem, but fix it? Are new rings necessary?

You should leak down the engine to help determine how severe the problem is, and how consistent it is from one cylinder to the next.  Is the engine using much oil?

With proper breathers, you should not need a puke tank.