Need help identifying a motor - 572 or 454?
 

Hi everyone,
Long time reader, first time poster here.
I'm interested in buying a particular used offshore boat from the 1980s.
This boat is a bit of an anomaly (I'll probably have more questions about it later), but based on the photos looks in fair shape...at least fair enough to get me to go see it in person.

Here's the part I'm having doubts about. The current seller (a used boat dealer) says that the previous owner put a "new 572" motor in it 2 years ago.
I asked for a photo of the motor, and to me it looks like a L29 Mercruiser 7.4L (454) from the late 1990s, with the plastic covers removed.
I was able to identify that unique looking intake manifold and the exhaust risers which look JUST like the stock 7.4L units in the photo below.
I'd like to post a photo, but I'm a newbie and not allowed. However, here's a link to what a normal 7.4L looks like complete with the covers on it.

https://i.ytimg.com/vi/DjKNG7LhOao/maxresdefault.jpg


My question: is there any chance that someone could take a 572 block and put those L29 454 heads/intake/exhaust on it? I've heard it could be done with a 502 block, but a 572 block?
Is there such a thing as an old school 572 block? I always assumed that when someone says 572, they're talking about the hot rod crate motor ZZ572 from GM...
I hope it's not an old Cadillac block...

I welcome all opinions... I'm a newbie...Either way, I'm going to go check it out tomorrow to see if I can find the block ID numbers and finally settle it....

Thanks!

I totally agree with you already mentioning for checking - on the side of the blocks GM has their number codes - run that number and it will tell you what the block is.

I doubt its a 572 a 572 would be a tall deck intake would need spacers.

My guess would be a typo for a 502, which is still a good motor.

unless its a 4.375 x 4.560 bore short deck.

If someone did put a 572 shortblock , under those L29 heads/intake setup, they need to lay off the drugs :bong:

post the 8 diget number that is cast into the flywheel area and i will tell you what block you have.i doubt it is a 572.

Puff puff give.

Tell the used boat dealer he should sell what he's best at. Jokes. What a Joker.

You can post pics on a remote site like Photobucket or wherever and link it back here.

Yup. Classic case of someone asking for more toke, I mean torque, no I mean toke, Ha !

Anything is possible but doubtful. You had me at used boat dealer. Ha. Like MT said its not out of realm to build a short deck 572 or get a mail order. Companies are all over the place but the L29 heads is almost a dead giveaway. But then again I've seen some joe dirts buddies builds who really do need to lay off the pipe and go back to go carts.

Simple nobody is going to spend the money on a 572 and put stock logs on it. Case closed. You will get hosed buying this.

Let us know what you find out. I have a feeling you'll be heading over just because. Take a picture of the salesman. Bet he has a mustache and early 80's glasses.

There is no way to tell externally whether or not its a 502, 540 or 572.
They all can use the same (502) engine block and just use different bore and stroke combos.

most 540 or 572.s are internally balanced,a stock 502 is externally balanced.if the engine has a stock gm externally balanced balancer it is most likely a 502.

keyword is "used boat salesman" be lucky if its a 454, 572's are tall deck blocks and you could see intake spacers easily...

as alresdy stated,not all 572,s are built on a tall deck block but i agree it most likely is not a 572.

Thanks for the tip SB! Let's see if this works. I took the photo the dealer sent me of the motor and placed it beside a stock image photo of a normal L29 complete motor from the Internets:

http://s33.postimg.org/i4flpxqz3/454comparison.jpg

Unfortunately, the dealer cancelled my appointment today as he was out delivering another boat. So I'm going to have to wait until the weekend.
Until then, feel free to play "spot the differences" between the two photos above. Other than the plastic engine covers, any other comments as to the shape of the engine or anything that looks out of place?
I'm not asking for a marine survey from a photo...just hoping folks with more experience might see something wrong.
Already I don't like that the exhaust tubes aren't double-clamped. I'm pretty sure that's not up to code. LOL.

I'll keep you guys posted when I get a chance to see the motor and boat in person this weekend. Thanks again!

Oh yeah LOL he might. After I saw the photos he sent me of the boat, I already knew the description he gave me over the phone was not very accurate.
Also, he told me the boat had an Alpha One outdrive, which made no sense behind a 572, or any other big block. Sure enough, when I saw the photo of the outdrive, it was clearly a Bravo One.
He seems like a nice enough guy over the phone...at this point I'm going there this weekend to see the boat with a very open mind...

Wonder if he's the guy that last year sold a guy on here a 10yr older Fountain than what was said.

There is a 3yr span when 330hp 454's came with Alpha's behind them. LAte 80's.

Bilge blower motor is missing the other hose. Boom !

Your photo is too small to really see much.

That's disturbing. LOL. I thought Alpha Ones are only reasonably meant to handle small block amounts of torque....maybe that's why they only did that for 3 years. Hah.

That package was called a MAgnum too. Doh ! 80's where tough with allot of things, not just boats.

Hey good eyes SB!

I smelled the fumes. THat is what I do during the day, smell fumes.

The 3 year deal was because they where transitioning away from the TRS drive (which had a transmission) to the Bravo, which does not have a transmission.

It's not routed right either. Proper bilge blower rigging and operation can and will save your and others life or skin.

Ask and you will receive...just getting the hang of this image hosting thing. This is the biggest photo I have...
I'm a gonna do some reading up on bilge motors then! Thanks for the tips thus far!

http://s33.postimg.org/7bmt1aztb/mercruiser_L29.jpg

Like pretty much everyone else has come to the conclusion I'd bet anything it's a 454. Not real real rigged either. Indication engine prolly was in and out frequently. Salt water boat if I was to guess also. My gut instinct unless you can figure on an engine right from the get go then I'd pass. At times in the past I use to like those sleeper stroked engines with 454-330 stickers however I doubt this be the case. Just looks like a poorly maintained if at all boat with issues that's why it was traded in. Just my 2 cents

14 Apache had a very valid point also regarding the exhaust. 1)just doesn't make sense to go through the expense of a 572 and have stock exhaust manifolds. 2) perhaps he did a quick sale on aftermarket exhaust to recoup some monies before trade in. 3) I can't imagine what the exhaust valves look like as well as the Pistons if those were the manifolds used. Heat builder! Also some wire loom clamps not screwed down and hose clamps don't line up and mismatched, wires hanging, throttle and shifter cables look freshly thrown in without being secured, exhaust host cut with a utility knife, clamps not on straight. etc. You get the idea.

meticulous detail says a lot about a boat and so does non detail. It's a trade in for a reason. Guy didn't want anybody coming back on him. I've owned a dozen boats and never traded one in.

How much for the boat? This boat has the name got screwed on it. There is nothing in the picture that shows the guy will spend the money on a 572 zero.

Why are we still mentioning 572 ?

What sucks is some first time buyer will end up with this at some point. I have s feeling it won't be anyone from OSO. :readinghelp::readinghelp::readinghelp:

Did we rule this out for certain. I missed a page.

I may have missed it, what year, make, model is this boat ?

Let's just send a drone over this thing and drop a little c4 care package in it and save the OP his trouble.

thats a GM perf parts or truck intake isn't it ? not a merc ?

Thanks for your comments Getrdunn. I'm curious, what gives you the impression that it was a salt water boat? I'd like to look more into that. Is there some hints that I can look for in a boat?
Also, the dealer told me that it wasn't traded in, it was a boat that the dealer bought from a private seller in Vegas or Nevada or something like that. I can't remember where exactly now.

That's a good question, and believe it or not, the dealer isn't exactly sure either. LOL. I will start a different thread altogether on that question, as I get the feeling that will be an even more fun mystery! LOL.

Well, based on the side-by-side photo I posted on page 2 of this thread, comparing the mystery motor (left) to the stock L29 Mercruiser 7.4L Magnum (right), they would appear to have the same manifolds...just that the right one has the factory plastic covers on it.

I don't think it's entirely ruled out yet. I did more research and it would appear that stock 454 block with a standard deck height of 9.80 inches (assuming the Merc blocks are the same or similar to the GM auto/truck big blocks) can be bored/stroked out all the way to 598 cubic inches:

Displacement = Bore x bore x stroke x 0.7854 x number of cylinders
Displacement = 4.5 x 4.5 x 4.5 x 0.7854 x 8
Displacement = 572 ci

Standard Deck Height: 9.80

Bore Stroke Cubic Inches
4.25 4.00 454
4.31 4.00 467
4.31 4.25 496
4.50 4.25 540
4.56 4.25 555
4.60 4.50 565
4.50 4.50 572
4.625 4.25 571
4.56 4.50 588
4.60 4.50 598

The table above is from the good folks at Hot Rod magazine:
http://www.hotrod.com/how-to/engine/...rder-strokers/