Thru hull exhaust

[Guitarhead]

Not sure how you know that as the same 454 block that went into a chevelle, also went into trucks, boats, ambulances and other things.

Hope the core plugs are brass, and the cylinder gaskets are marine. Hope the cam is either Marine or Truck

Haha yeah I meant to say truck etc it was late sorry .

im assuming, it has 400 hours

 

[Scott Danforth]

Haha yeah I meant to say truck etc it was late sorry .

im assuming, it has 400 hours

again, how would you know? the mark IV BBC block has passenger high performance on the side of the block and has been installed in everything I listed, as well as gensets and forklifts as a natural gas engine

the only thing I do know is the air cleaner is not a marine spark arrestor based on your pictures and there is a bit of big box store aluminum angle scabbed in as a throttle bracket. that makes me wonder what else is not marine on the engine.

have you made sure the starter, alternator and ignition are marine?

 

[Guitarhead]

No I havent. I have just been running it

 

[Commander_47]

In 1990 the 454 SS motor was introduced for trucks. This motor is a monster with fuel injection and vortec heads. It is easy to tell which is which by the block number. I know, I have one and built it up for a Corvette installation.

Also, there is a myth about so called "marine" accessories on boats. Marine is supposedly "hardened". That is not true anymore. All electric connections are safe now.

The big difference is the power output. If you are running two batteries and lots of accessories, you need a robust alternator. If you just go to Auto Zone and buy a cheap one, it won't generate enough power. Make sure you get one that will support your power draw. Same with a starter.

Also, do you really think that a car motor under a hood is less susceptible to damage from water than a boat in an enclosed engine compartment? I submit that the car motor and accessories take a much bigger beating from the garbage kicked up from the street and weather than being on the water.

I, personally, would not cut holes in the transom. I just don't see this as being a very good idea. If the the exhaust has a couple of bends in it, how much horsepower are you really gonna lose in your boat? Not many.

Paying for a custom exhaust is definitely an option....but why? Are you going racing? Do you just want to tool around at break neck speed? I believe your SS 454 will get the job done regardless.

It looks to me like you could easily find some marine elbows to fab an exhaust.

 

[Guitarhead]

Wow that is clean .yeah I looked at the numbers on the block and I think it is from 70-73 . I can’t drill new holes anyways , see picture in reply above . Yeah I think I’m just going to buy elbows . The boat runs 65 now , that is with two full tanks and two people, it is heavy boat . I know I can’t get much fast without serious mods . But after I get the thru hulls attached I am going to try a 27p prop, it has a 23p now .

 

[kenny nunez]

I went to a plumbing supply warehouse and with a sample of the rubber exhaust hose was able to get 4 close 90* copper street els to make the connection.
After I had them “clocked” I then silver soldered them together.
I also had a boat that was made where the exhaust had to exit further out from center. Since I cannot judge the distance you have to work in you may have to shorten the straight section of the fittings.

 

[Guitarhead]

I went to a plumbing supply warehouse and with a sample of the rubber exhaust hose was able to get 4 close 90* copper street els to make the connection.
After I had them “clocked” I then silver soldered them together.
I also had a boat that was made where the exhaust had to exit further out from center. Since I cannot judge the distance you have to work in you may have to shorten the straight section of the fittings.

Do you have any pictures of the elbows ?

 

[2550SX]

Wow that is clean .yeah I looked at the numbers on the block and I think it is from 70-73 . I can’t drill new holes anyways , see picture in reply above . Yeah I think I’m just going to buy elbows . The boat runs 65 now , that is with two full tanks and two people, it is heavy boat . I know I can’t get much fast without serious mods . But after I get the thru hulls attached I am going to try a 27p prop, it has a 23p now .

What RPM is that engine spinning at 65mph?

 

[kenny nunez]

Sorry no pictures, it was when I had my shop years ago.
Basically what it turns out to be is a swing joint. I believe you have 4” exhaust hose, the fittings will be close either way to the hose size.

 

[Paintman1960]

Am i missing something here? How are you using it without Exh. thru the transom?
Looked again, I see how now

 

[Commander_47]

I looked at the numbers on the block and I think it is from 70-73 .

The block numbers will absolutely tell you what year it was made. If it was a 70-73 then it definitely was from a Camaro, Chevelle or Corvette.

For 1970, the ultimate big-block, the 454, appeared. Initially offered as the 390-hp LS5, it was augmented in ’71 only by the 425-hp LS6. Beginning in 1972, horsepower numbers dropped to 270 due to the switch to net horsepower ratings and the implementation of emissions regulations.

The mighty 454 was not put into trucks until 1974. And even then, it was an option.

Decode the engine block number on the flat tab. The first letter represents the engine manufacturing plant, followed by four numbers for the month and day of manufacture. The next three letters are the engine code which tells the year, amount of horsepower and vehicle model the engine was originally manufactured for. The engine ID number must be cross-referenced with a GM listing. Chevy-Camaro has a complete listing for all 454 c.i.d engines.

 

[Scott06]

In 1990 the 454 SS motor was introduced for trucks. This motor is a monster with fuel injection and vortec heads. It is easy to tell which is which by the block number. I know, I have one and built it up for a Corvette installation.

Also, there is a myth about so called "marine" accessories on boats. Marine is supposedly "hardened". That is not true anymore. All electric connections are safe now.

The big difference is the power output. If you are running two batteries and lots of accessories, you need a robust alternator. If you just go to Auto Zone and buy a cheap one, it won't generate enough power. Make sure you get one that will support your power draw. Same with a starter.

Also, do you really think that a car motor under a hood is less susceptible to damage from water than a boat in an enclosed engine compartment? I submit that the car motor and accessories take a much bigger beating from the garbage kicked up from the street and weather than being on the water.

I, personally, would not cut holes in the transom. I just don't see this as being a very good idea. If the the exhaust has a couple of bends in it, how much horsepower are you really gonna lose in your boat? Not many.

Paying for a custom exhaust is definitely an option....but why? Are you going racing? Do you just want to tool around at break neck speed? I believe your SS 454 will get the job done regardless.

It looks to me like you could easily find some marine elbows to fab an exhaust.

Marine rating on accessories has nothing to do with being hardened , what ever that meas.
marine rating is for components designed to prevent electrical sparks and gas vapors from igniting. This challenge is quite different in an enclosed marine engine compartment vs an engine on a car or truck where fuel valors can expell under the car.

main differences for components are

electrical like alternator, distributor, starter they are explosion proof typically screening and shielding which prevents sparks from getting outside the housing
carbs different bowl vents to prevent fuel spillage if bowl over fill and will have a port for mechanical fuel pump diaphragm rupture relief
mechanical fuel pump have a separate small line coming off that incase the diaphragm ruptures it will push fuel into the carb top and engine vs into the bilge.
water pumps marine have brass bronze or stainless impellers and backing plate and can run in either direction.

the basic engine itself is basically the same as a truck engine except marine head gaskets, brass freeze plugs, and cam has overlap and lobe separation angle such that you wont get reversion.

 

[kenny nunez]

Try googling, Ace Race parts. They have stainless close mandrel bends a lot cheaper than copper.

 

[2550SX]

The block numbers will absolutely tell you what year it was made. If it was a 70-73 then it definitely was from a Camaro, Chevelle or Corvette.

For 1970, the ultimate big-block, the 454, appeared. Initially offered as the 390-hp LS5, it was augmented in ’71 only by the 425-hp LS6. Beginning in 1972, horsepower numbers dropped to 270 due to the switch to net horsepower ratings and the implementation of emissions regulations.

The mighty 454 was not put into trucks until 1974. And even then, it was an option.

Decode the engine block number on the flat tab. The first letter represents the engine manufacturing plant, followed by four numbers for the month and day of manufacture. The next three letters are the engine code which tells the year, amount of horsepower and vehicle model the engine was originally manufactured for. The engine ID number must be cross-referenced with a GM listing. Chevy-Camaro has a complete listing for all 454 c.i.d engines.

Chevelle or corvette. No camaro.

 

[Guitarhead]

What RPM is that engine spinning at 65mph?

I think it was 4500 or 4600 I’ll check it this weekend

 

[Guitarhead]

The block numbers will absolutely tell you what year it was made. If it was a 70-73 then it definitely was from a Camaro, Chevelle or Corvette.

For 1970, the ultimate big-block, the 454, appeared. Initially offered as the 390-hp LS5, it was augmented in ’71 only by the 425-hp LS6. Beginning in 1972, horsepower numbers dropped to 270 due to the switch to net horsepower ratings and the implementation of emissions regulations.

The mighty 454 was not put into trucks until 1974. And even then, it was an option.

Decode the engine block number on the flat tab. The first letter represents the engine manufacturing plant, followed by four numbers for the month and day of manufacture. The next three letters are the engine code which tells the year, amount of horsepower and vehicle model the engine was originally manufactured for. The engine ID number must be cross-referenced with a GM listing. Chevy-Camaro has a complete listing for all 454 c.i.d engines.

I’ll post a picture of the number on the block when I get off wor

 

[todhunter]

If you need tight bends, Pegasus Racing offers a 4" stainless "donut" mandrel bend. It's got a 4" bend radius - that's as tight as you're going to get without doing pie cuts.

 

[Scott Danforth]

In 1990 the 454 SS motor was introduced for trucks. This motor is a monster with fuel injection and vortec heads. It is easy to tell which is which by the block number. I know, I have one and built it up for a Corvette installation.

Also, there is a myth about so called "marine" accessories on boats. Marine is supposedly "hardened". That is not true anymore. All electric connections are safe now.

The big difference is the power output. If you are running two batteries and lots of accessories, you need a robust alternator. If you just go to Auto Zone and buy a cheap one, it won't generate enough power. Make sure you get one that will support your power draw. Same with a starter.

Also, do you really think that a car motor under a hood is less susceptible to damage from water than a boat in an enclosed engine compartment? I submit that the car motor and accessories take a much bigger beating from the garbage kicked up from the street and weather than being on the water.

I, personally, would not cut holes in the transom. I just don't see this as being a very good idea. If the the exhaust has a couple of bends in it, how much horsepower are you really gonna lose in your boat? Not many.

Paying for a custom exhaust is definitely an option....but why? Are you going racing? Do you just want to tool around at break neck speed? I believe your SS 454 will get the job done regardless.

It looks to me like you could easily find some marine elbows to fab an exhaust.

you really dont understand marine engines and SAE J1171 requirements do you?

 

[2550SX]

I think it was 4500 or 4600 I’ll check it this weekend

23" sounds about right. a 27" prop will bring those RPM's down a lot and make the boat harder to get up on plane.

 

[Commander_47]

you really dont understand marine engines and SAE J1171 requirements do you?

hahah, so you say.

But the facts are the facts. My mercruiser came with a standard 4 barrel Rochester carb, standard starter and alternator.

If you make sure your engine compartment is sufficiently vented, you will never have an "explosion". Period, end of story.

If you prefer to spend three times the amount of money to keep a pocket cruiser running. Have at it.

Most of the fears regarding old time electronics don't exist anymore.

Marine Alternator Features​

In order to meet these demands, alternators built for marine use have features not found in automotive-grade units:

• Spark screens that meet U.S. Coast Guard standards to eliminate the alternator as an ignition source (A SPARK ARRESTOR CAN BE HAD FOR LESS THAN 10.00 FOR ANY ALTERNATOR. OR YOU CAN GET THE SPARK ARRESTED ALTERNATOR AT WAL MART FOR 100.00 HERE.
• https://www.walmart.com/ip/NEW-63A-...TS-MARINE-AL513X-E27FBA-E27F10300BA/628296618
• OR: YOU COULD GET AN AUTOMOTIVE ALTERNATOR WITH SPARK PROTECTED BRUSHES
• OR: YOU COULD GET A SEALED ALUMINUM CASE ALTERNATOR).
• Double-insulation (TOTAL OVERKILL. NORMAL INSULATION IS FINE, AND ALSO WATERPROOF, AS EVIDENCED BY ALL THE CARS ON THE ROADS IN RAIN) to eliminate electrical shock in wet conditions and prevent sparks
• Dual fans ( TOTALLY NOT NECESSARY. IF YOU FEEL THE NEED, THEN BUY A DUAL FAN. ALL ALTERNATORS COME WITH FANS AND HEAT SINKS. ALL OF THEM) and large heat sinks for self-cooling under high, continuous loads
• Stainless steel bearings, corrosion-resistant metals and heavy-duty coatings(OVERKILL, YOU MIGHT WANT THIS IN SALT WATER. NOT NECECESSARY AT ALL IN FRESH WATER)
• High output at low RPMs to match marine diesel engine operating conditions(LIKE I SAID EARLIER, GET AN ALTERNATOR BIG ENOUGH FOR YOUR NEEDS0
• Battery sensing regulators for high-efficiency battery charging and detection of battery cell failure.(TOTAL OVERKILL. ALL REGULATORS DO THIS AND WON'T OVERCHARGE A BATTERY. IF YOU USE SEALED BATTERIES, NOT A PROBLEM ANYWAY.

PS: Spark arrester here for just about any standard alternator.

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