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MTBMAC
06-02-2009, 04:02 PM
I am currently restoring a fankinstine of a boat. The current Enging that is in it is a GM 327. My questions are 1st, Can I swap it out with a 350? 2nd Will my current engine mounts line up? What about my current manifolds and other neccessary parts? and 3rd, Are there any differences between an Auto and Marine engine, other then the intake and exhaust manifolds?

Thanks for your help

CantRepeat
06-02-2009, 05:15 PM
The 327 you have should have all the same bolt holes as any 350.

The Carbs are different on the marine models as well.

rob935
06-02-2009, 05:24 PM
marine engines are basically the same as auto engines but most of the ancillaries are marinised in order to last in tough damp and hot conditions, standard auto parts such as starter motors,alternators etc would burn out in no time at all so they may look the same but in reality are quite different .

bcampbe7
06-02-2009, 05:34 PM
Not only that but boat engine compartments tend to hold fuel vapors. Marine starters and alternators are built to reduce/eliminate the possibility of creating spark so that your boat doesn't go boom.

flipper
06-02-2009, 05:52 PM
Don't know for a fact, but I was told the valves are different also to withstand the heavy load and heat that a boat engine faces.

denverd1
06-02-2009, 05:55 PM
Flip, can you confirm that? Looks like I'll be tearing my 351W down again and I'd like to know the details on the valves. Blew a head gasket saturday...

flipper
06-02-2009, 05:57 PM
I can find out, or somebody that know a lot more than I ever will like Jim or engine nut may chime in.

panshovel68
06-02-2009, 07:44 PM
You might as well get used to changing engines if your going to put a automotive engines in your boat! The heads and cams are usually different, different torque curve. Boats have a single gear trans. Do it right the first time and repower with a marine engine. If you could just slap a car engine in your boat, why would companies like PCM and Indmar be in buisness? I just repowerd a ps190. Took out the ford and put a PCM chevy in. It wasnt cheap but it was a plug and go operation. And I am more than satisfied with the turn out! I have no problem pulling three footers goin 40mph.

CantRepeat
06-02-2009, 10:17 PM
You might as well get used to changing engines if your going to put a automotive engines in your boat! The heads and cams are usually different, different torque curve. Boats have a single gear trans. Do it right the first time and repower with a marine engine. If you could just slap a car engine in your boat, why would companies like PCM and Indmar be in buisness? I just repowerd a ps190. Took out the ford and put a PCM chevy in. It wasnt cheap but it was a plug and go operation. And I am more than satisfied with the turn out! I have no problem pulling three footers goin 40mph.

That's not true by any measure. Indmar purchased those motors from Ford with factory cams, P40 heads and standard pistons. Other then the external parts they are automotive engines with automotive parts.

Indmar and PCM are in business because Ford and Chevy don't build boats.

panshovel68
06-02-2009, 11:22 PM
That's not true by any measure. Indmar purchased those motors from Ford with factory cams, P40 heads and standard pistons. Other then the external parts they are automotive engines with automotive parts.

Indmar and PCM are in business because Ford and Chevy don't build boats.

Well then put a car motor in your boat!

Besides duty cycle there are other important differences. A marine engine’s core plugs are corrosion resistant bronze. The camshaft is ground to different specifications, most often to maximize low end torque. Also, the camshaft profile is different. Valve overlap (the time when both intake and exhaust valve are open) is shortened to minimize the chance of water being sucked out of the exhaust and into the combustion chamber. Gaskets are premium quality for better sealing and corrosion resistance

Electrical, ignition, and fuel system components on Indmar engines are designed and manufactured to comply with U.S. Coast Guard rules and regulations to minimize risks of fire or explosion. Use of replacement electrical, ignition, or fuel system components, which do not comply with these rules and regulations, could result in a fire or explosion hazard and should be avoided. Also, many other components on Indmar engines are designed and manufactured differently from standard automotive parts. Marine engines operate at or near full-throttle for most of their lives. They are also expected to operate in both fresh and saltwater environments. These conditions require numerous special parts. Care should be exercised when replacing marine engine parts, as specifications are quite different from those of the standard automotive

The bottom line, an unmodified automotive engine is totally inappropriate for a boat motor. Its torque curve won’t meet the needs of a boat, its light-duty components won’t long survive the rigors of marine usage, and you risk blowing yourself out of the water. You decide




According to Indmar and Marine engine digest.
Although they may be the same heads and camshafts they are reworked. That is straight off Indmars website!

BTW I never knew Indmar and PCM build boats:confused:

pram
06-03-2009, 02:23 AM
Well then put a car motor in your boat!

Besides duty cycle there are other important differences. A marine engine’s core plugs are corrosion resistant bronze. The camshaft is ground to different specifications, most often to maximize low end torque. Also, the camshaft profile is different. Valve overlap (the time when both intake and exhaust valve are open) is shortened to minimize the chance of water being sucked out of the exhaust and into the combustion chamber. Gaskets are premium quality for better sealing and corrosion resistance

Electrical, ignition, and fuel system components on Indmar engines are designed and manufactured to comply with U.S. Coast Guard rules and regulations to minimize risks of fire or explosion. Use of replacement electrical, ignition, or fuel system components, which do not comply with these rules and regulations, could result in a fire or explosion hazard and should be avoided. Also, many other components on Indmar engines are designed and manufactured differently from standard automotive parts. Marine engines operate at or near full-throttle for most of their lives. They are also expected to operate in both fresh and saltwater environments. These conditions require numerous special parts. Care should be exercised when replacing marine engine parts, as specifications are quite different from those of the standard automotive

The bottom line, an unmodified automotive engine is totally inappropriate for a boat motor. Its torque curve won’t meet the needs of a boat, its light-duty components won’t long survive the rigors of marine usage, and you risk blowing yourself out of the water. You decide




According to Indmar and Marine engine digest.
Although they may be the same heads and camshafts they are reworked. That is straight off Indmars website!

BTW I never knew Indmar and PCM build boats:confused:

hahahahahahahahaqhahahahahaha

put that in your pipe and smoke it

CantRepeat
06-03-2009, 05:42 AM
Well then put a car motor in your boat!


BTW I never knew Indmar and PCM build boats:confused:

I said he external parts are different so why are you discussing that?

And who said Indmar or PCM built boats? I referenced that Chevy and Ford don't build boats, if they did, they'd build their own engines and therefor Indmar and PCM would not have a job. (smoke that, really?)

HAHAHAHAHAH, I don't smoke, sorry. Gezzz grow up a bit.

Having a discussion or disagreement sure brings out the kid in some of you people. It's like talking to my brother's kids.

panshovel68
06-03-2009, 10:53 PM
I said he external parts are different so why are you discussing that?

And who said Indmar or PCM built boats? I referenced that Chevy and Ford don't build boats, if they did, they'd build their own engines and therefor Indmar and PCM would not have a job. (smoke that, really?)

HAHAHAHAHAH, I don't smoke, sorry. Gezzz grow up a bit.

Having a discussion or disagreement sure brings out the kid in some of you people. It's like talking to my brother's kids.




Hey maristar....no disrespect was intended! If it seemed that way I am sorry! The Indmar and PCM was a little sarcastic, but thats it. Once again I apologize.

:)

PolarBear
06-03-2009, 11:30 PM
92 - Dude, what are you doing on this website at 3:45AM! Boring night job?

CantRepeat
06-04-2009, 08:47 AM
92 - Dude, what are you doing on this website at 3:45AM! Boring night job?

I've been in the Army for 23 years, that's the time I get most every morning. I'm hoping I can change once I retire.

panshovel68
06-04-2009, 06:22 PM
I've been in the Army for 23 years, that's the time I get most every morning. I'm hoping I can change once I retire.

Wow, I thought I got up early.

Whitfield
06-04-2009, 09:53 PM
The PCM on my old boat was a counter rotaiton engine.

The motor was redesigned by PCM to run backwards.

Folks at Skidim commented about using the counter rotation engine to turn the prop the other direction for optimal ski wake hull performance and use the torque thrust counter rotation to help offset the drivers weight.

dds
10-21-2009, 02:06 AM
wondering if anyone can help out with some questions?

if the concensis is that the heads are the same...... any issues with looking for some GT40-p heads from the automotive side rather than trying to seek out some marine GT40-p heads?

What about ordering some GT40-x heads from ford racing?

are there any concerns with dissimilar metals in the cooling system (raw water intake). the previous owner was a plumber and he installed a shower system using copper T fittings. there is a mixture of copper, aluminum and cast iron......

Thank you!!

H20skeefreek
10-21-2009, 07:51 AM
GT40-P heads are GT40-P heads.

etduc
10-21-2009, 10:38 AM
wondering if anyone can help out with some questions?

if the concensis is that the heads are the same...... any issues with looking for some GT40-p heads from the automotive side rather than trying to seek out some marine GT40-p heads?

What about ordering some GT40-x heads from ford racing?

are there any concerns with dissimilar metals in the cooling system (raw water intake). the previous owner was a plumber and he installed a shower system using copper T fittings. there is a mixture of copper, aluminum and cast iron......

Thank you!!

I purchase standard Ford heads (reman.), from local auto store. $400(pr) + core. (Heads skimmed. I did my own porting and port matching.) They didn't have any Gt-40 at the time, normally sold for $550.00 + core. If your compression is remaining near stock, going beyond Gt40-p, won't get you more bang. I did use a new Ford Racing alum. intake on my boat, $90.00 from ebay. That did make a big difference.

Copper, aluminum, iron, not a good combo, for your shower. Replace copper with brass or high temp pvc. (Basically, dissimilar metals, shouldn't touch each other. Need a barrier, isolator, between. Problem, water acts as a bridging agent. ) Winterizing block, rust inhibator anti-freeze, helps reduce corrosion. BUT it will still happen.

JimN
10-21-2009, 11:31 AM
I purchase standard Ford heads (reman.), from local auto store. $400(pr) + core. (Heads skimmed. I did my own porting and port matching.) They didn't have any Gt-40 at the time, normally sold for $550.00 + core. If your compression is remaining near stock, going beyond Gt40-p, won't get you more bang. I did use a new Ford Racing alum. intake on my boat, $90.00 from ebay. That did make a big difference.

Copper, aluminum, iron, not a good combo, for your shower. Replace copper with brass or high temp pvc. (Basically, dissimilar metals, shouldn't touch each other. Need a barrier, isolator, between. Problem, water acts as a bridging agent. ) Winterizing block, rust inhibator anti-freeze, helps reduce corrosion. BUT it will still happen.

Dissimilar metals that cause a galvanic reaction shouldn't be in contact but if brass plugs and other water fittings are used, tehy won't rust together the way steel or cast iron fittings will. Copper should be OK for a while but the zinc in brass makes it much more durable.

Thrall
10-22-2009, 10:33 AM
Check the exhaust manifold bolt pattern on the 327 and 350. I'm not sure what years are different, but I remember having different bolt patterns between a late '60s 307 and a mid '80s 305, CHevy motors. Otherwise, I think all the rest of the bolt holes, mounts, bellhousing, etc are the same.

Laurel_Lake_Skier
10-26-2009, 10:41 PM
wondering if anyone can help out with some questions?

if the concensis is that the heads are the same...... any issues with looking for some GT40-p heads from the automotive side rather than trying to seek out some marine GT40-p heads?



These heads will work fine. You can have the freeze plugs replaced with bronze/brass for a bit more resistance to corrosion in the cooling systems we run in the boats. When I bought my new GT-40-p heads a few years back Clearwater Cylinder Heads installed the brass plugs prior to shipping the heads out to me at no additional cost.