Blown pre-vortec 4.3. Upgrade to vortec? V8? Truck engine?

[Bumperlt12]

Hello,

I have recently purchased a 91 boat with a (91?) 4.3 and alpha one. Everything is in good shape, except the engine. Water in oil, sat with head removed for a while. Carburetor and intake manifold are in poor condition and will probably be replaced as well.

I don't know if what I have is rebuildable, even if it is, the PO used it in salt water without fresh water cooling. Makes me uneasy.

So I've been reading up here all day and the only info I don't have is pricing cause everything is closed! Right now I am leaning towards a Jasper reman 4.3 for an easy process.

Can I get a vortec 4.3 and new intake manifold and still have all my pre-vortec bolt ons work?

Can i get an "S10" longblock and literally only swap the plugs to brass and call it good?

 

[achris]

Hello,

I have recently purchased a 91 boat with a (91?) 4.3 and alpha one. Everything is in good shape, except the engine. Water in oil, sat with head removed for a while. Carburetor and intake manifold are in poor condition and will probably be replaced as well.

I don't know if what I have is rebuildable, even if it is, the PO used it in salt water without fresh water cooling. Makes me uneasy.

Why? My 4.3 is 14 years old, only ever used in salt water, and not closed cooled. Still in great shape.

So I've been reading up here all day and the only info I don't have is pricing cause everything is closed! Right now I am leaning towards a Jasper reman 4.3 for an easy process.

Can I get a vortec 4.3 and new intake manifold and still have all my pre-vortec bolt ons work?

Yes.

Can i get an "S10" longblock and literally only swap the plugs to brass and call it good?

You'll need to do the head gaskets too.

Chris........

 

[Furbird]

This has been a pandora's box type of question. From my personal experience, my 02 boat has an 01 Vortec out of a Chevrolet Express van. The freeze (core/casting/whatever) plugs in mine were brass from the factory but were replaced anyway. The camshaft is (allegedly) different but the truck cam (again, allegedly) works. My cam was swapped from the Mercruiser to the truck engine. The truck head gaskets will work with raw water cooling if used in fresh water only (which is all mine is used in.) The intake will have to be a marine one, along with the raw water pump (can't use a vehicle water pump.)

So to answer your question, yes to a point, you can use all of your peripherals from your old boat engine on a truck engine. As far as going from non-Vortec to Vortec, I believe someone else recently posted that same question and the answer was yes it will all bolt up. But the real question you should be asking yourself is do you want to go through all that work for a junkyard engine with unknown history put into a boat where it's going to run at a high RPM all the time? If you get a used engine, it needs to be gone through to ensure it's not going to have some major failure when put under that kind of stress, and if that's not something you're capable of doing, the cost and time invested may surpass buying one already rebuilt. In my case the previous owner was a machinist by trade and went through the engine prior to installation (but let's be honest, it's a 4.3 out of a van, those things will run well over 500,000 miles if you keep oil and coolant in them so he didn't have to do much by his own admission.) Still, if you don't open it up and check, you may miss a 5 dollar part that takes out a block and you're back at square one.

 

[Bumperlt12]

Looks like the guy gave me a rochester quadrajet carb, which I don't think was the oem carb.

I think the vortec 4.3 has an 8 bolt intake manifold, while my pre vortec is 12 bolt.

Assuming I'll need to buy a new intake manifold and carburetor, can someone point me in the right direction for a combination that would work well on a vortec 4.3?

 

[Rick Stephens]

Merc had a Quadrajet as well as a Weber for the 4 barrel carb version. Nothing wrong with using either.

On my engine, when I repowered my boat, the Quadrajet with a square to spread bore adapter was too tall to fit under the doghouse. So I went with a 1409 Edelbrock, which is an exact copy of the Weber OEM carb. I stuck that on a standard Edelbrock Performa square bore intake. There is a more expensive marine version with brass water passages, but I only run in clear fresh water. I REALLY like the 1409. PM me if you get one and I will assist in getting it calibrated properly. Do not buy the 1485 calibration kit for the 4.3L from Edelbrock. It is useless.