4.3 mercruiser vs vortec pistons

[jknowles123]

Hey all,

My 4.3 mercruiser blew up recently and I'm working on getting my donor 4.3 vortec converted.

I was talking to the guys st my local marine shop today and they tell me the marine engines have thicker cast pistons to handle the heat...

Anyone know if this is true or can I just run the stock vortec pistons?

 

[Scott Danforth]

Hey all,

My 4.3 mercruiser blew up recently and I'm working on getting my donor 4.3 vortec converted.

I was talking to the guys st my local marine shop today and they tell me the marine engines have thicker cast pistons to handle the heat...

Anyone know if this is true or can I just run the stock vortec pistons?

Bunk

Pistons are still cheap flat tops with 4 valve reliefs

What did the motor come from? What year boat do you have?

Is the motor a true vortec headed motor or one with the vortec decals.

 

[jknowles123]

Bunk

Pistons are still cheap flat tops with 4 valve reliefs

What did the motor come from? What year boat do you have?

Is the motor a true vortec headed motor or one with the vortec decals.

I thought so...

True vortec. Believe is a '00 or somewhere around there. Don't worry I have good merc heads. Actually managed to pick up a 4 barrel intake for 50 bucks CAD the other day

 

[jknowles123]

I thought so...

True vortec. Believe is a '00 or somewhere around there. Don't worry I have good merc heads. Actually managed to pick up a 4 barrel intake for 50 bucks CAD the other day

Boat and original engine are 93

 

[Scott06]

A lot of bunk theories on marine vs automotive. Marine engines are basically a truck engine .

Is the donor engine out of a car or truck. if car you will need to swap the cam . Truck cams are close enough to marine cams to work. Swap head gaskets for marine and freeze plugs for brass or stainless and you should be good to go . Use all the marine fuel and electrical components.

 

[jknowles123]

A lot of bunk theories on marine vs automotive. Marine engines are basically a truck engine .

Is the donor engine out of a car or truck. if car you will need to swap the cam . Truck cams are close enough to marine cams to work. Swap head gaskets for marine and freeze plugs for brass or stainless and you should be good to go . Use all the marine fuel and electrical components.

I believe out of a truck but I pulled my marine cam anyways... I'll check today.

Do you know the difference between the head gaskets? 600+ cad for a marine gasket set vs ~150 for auto

 

[Scott06]

I believe out of a truck but I pulled my marine cam anyways... I'll check today.

Do you know the difference between the head gaskets? 600+ cad for a marine gasket set vs ~150 for auto

Marine cam is best bet.

auto head gaskets will corrode in raw water vs marine that are stainless or composite to stand up to raw water vs antifreeze.

 

[Lou C]

I would see if you can get a Fel/Pro marine head gasket set for the 4.3, in the USA they are about $120 or so, the head gaskets are the same for the pre-vortec and Vortec, you would just need to get the Vortec intake gaskets those just use the best ones you can find, I don't know that any are marine specific. I used the Fel Pros on my top end overhaul 6 years ago and still fine no leaks all salt water use.
Marine vs truck engines I bet the only difference is the cam grind and the head gaskets and core plugs. The heads I put on mine I'm sure are just reman Chevy S-10 Blazer heads.

 

[Scott Danforth]

I thought so...

True vortec. Believe is a '00 or somewhere around there. Don't worry I have good merc heads. Actually managed to pick up a 4 barrel intake for 50 bucks CAD the other day

merc bought the heads from GM until 2015 when they built their own blocks and heads. the 00 truck motor you have has good vortec heads

your cam from 1993 may work, however suggest you get a proper roller cam for your motor

make sure to get a new circulating pump. the truck circulating pump will not work in a marine environment more than a few weeks. same goes for stock core plugs and head gaskets.

 

[jknowles123]

merc bought the heads from GM until 2015 when they built their own blocks and heads. the 00 truck motor you have has good vortec heads

your cam from 1993 may work, however suggest you get a proper roller cam for your motor

make sure to get a new circulating pump. the truck circulating pump will not work in a marine environment more than a few weeks. same goes for stock core plugs and head gaskets.

I would see if you can get a Fel/Pro marine head gasket set for the 4.3, in the USA they are about $120 or so, the head gaskets are the same for the pre-vortec and Vortec, you would just need to get the Vortec intake gaskets those just use the best ones you can find, I don't know that any are marine specific. I used the Fel Pros on my top end overhaul 6 years ago and still fine no leaks all salt water use.
Marine vs truck engines I bet the only difference is the cam grind and the head gaskets and core plugs. The heads I put on mine I'm sure are just reman Chevy S-10 Blazer heads.

Would you happen to have the part number for the felpro set

 

[Alumarine]

This might be the head gasket part number.

Part Details

www.drivparts.com

 

[Lou C]

375-17210
Keep in mind this comes with the intake gaskets for the pre Vortec you’ll need to pick up a set of Vortec intake gaskets. I believe the head gaskets & exhaust manifold gaskets are the same for both.