4.3L non vortec to vortec head swap

[Trev83]

Hey guys new here!
I’ll keep it short. Block is cracked and just pulled the engine. Don’t have much of a budget so trying to keep it under $2,000
the engine is a 93’ 4.3Lx non balance shaft, roller cam, 1 piece RMS. I have the opportunity to purchase a rebuilt pickup 4.3L vortec motor. (I know I know auto vs marine.... I will swap head gaskets, swap freeze out plugs to brass) my question is this:: I know the intake manifold on my engine most likely will not fit and I will need to go aftermarket that’s easy, the issue I can’t find an answer to is the exhaust manifolds.... will they bolt up to the vortec heads or do I need some newer style manifolds?

second questions is this. I was considering just doing a Jasper long block but heard they have had a poor reputation in the past.... what are your thoughts on say a summit racing block or a jasper block? Again I’d like to stay under $2000. My internals all looks good as the crack was found within minutes of the introduction of water into the engine. The block cracked right under the intake manifold.....

any help would be greatly appreciated

thanks!

 

[Rick Stephens]

Stay with a non-balance shaft block and stick Vortec heads and a Performa intake on it. If you are only running in fresh water, then you can get away with an all aluminum intake instead of a spendy marine version with brass inserts in the water passageways.

Your exhaust is no problem with the Vortec heads. All your other parts and pieces are a mess once you go to a newer block which will have a balance shaft, a different harmonic balancer, serp belts etc.

 

[Scott Danforth]

there are some used cast-iron vortec manfifolds on fleabay right now

exhaust ports are teh same.

your post is confusing as he#

what are you starting with? is the 93 motor yours or the one you found?

you cant put your internals into a new block except for the cam, crank and rods. new pistons, rings, bearings, etc. would be needed.

you should see your local engine builder. they most likely have core motors of every vintage and you can get a complete rebuild for under your $2k budget.

 

[Trev83]

The engine that is cracked is the 93’ 4.3LX engine. I ended up picking up a 02’ 4.3L engine for a few hundred bucks. It is does have a balance shaft but I pulled it apart today and it looks good. I ordered FelPro head gaskets and haven’t ordered the intake manifold yet. So far everything will transfer over from my 93’ 4.3 to my 02’ block and heads.

 

[Trev83]

Also, local engine builders is a no go. Everything here is $$$$. The local marine shop quoted me $12k to replace the engine in this thing... the second shop quoted me $6000 for a Jasper refurb. Engine. It’s nuts.

 

[Scott Danforth]

Also, local engine builders is a no go. Everything here is $$$$. The local marine shop quoted me $12k to replace the engine in this thing... the second shop quoted me $6000 for a Jasper refurb. Engine. It’s nuts.

thats your problem. you went to a local marine shop, not an engine machine shop. they quoted you a complete new bobtail. because they can only quote you new motors with full warranty. BTW, you can get a complete 6.2 bobtail for $12k. you can buy a new $350 longblock for $3k

a brand new 4.3 long block is $3k if you do the work yourself to build it to a bobtail. you pull the motor and take it to your local engine machine shop and they would only charge you about $1500-$1800 to rebuild a motor

or you can buy a reman 1993-1995 4.3 for about $2400 https://www.michiganmotorz.com/marine-engine-1993-p-310.html

no, not all your stuff will transfer over to the 2002 motor. only your exhaust, alternator, distributor and starter will. once you get a new intake, your carb will.

you will need new brass core plugs, new intake, new marine circulating water pump and you will have to custom tweek the accessory drive.

the front brackets will require some work, and the pulleys will require some spacers as the 96 and later used serpentine belts.

you jumped from the 93-95 generation of V6 over the 96-2000 into the 2001-2003 generation

its not in-surmountable, its just that it will take some work.

 

[Rick Stephens]

Scott is spot on ↑

Find a reputable NON-MARINE machine shop. This week picked up a complete 351 Windsor rebuil, using our core, for my kid's Ford pickup. $1800. Did everything and even came back as a long block assembled by the machinist. Just make sure they use brass core plugs and supply decent (suggest FelPro Marine) gaskets.

 

[nola mike]

I just did this with an '89 --> '01. My biggest issue was the harmonic balancer and the metric block. I ended up removing it and removing the CPS reluctor that's behind the timing cover. My water pump also wouldn't clear the composite timing cover, needed a new one. Also, the new block was partially metric whereas the old one was completely SAE. Tracking down the fasteners was a job. Other things you may need:
1, Throttle cable bracket that attaches to the intake if you're going from 2bbl-->4bbl carb. And flame arrestor for a 4bbl.
2. Starter. The holes on the starter were *just* too small for the metric bolts.
3. New dipstick assembly. It mounts in a different location on the side of the oil pan. Old one won't reach the bottom of the pan. It will check the level just fine, but you can't drain the oil from it. I got a drain tube instead that I can run out the bilge.

The pulleys and brackets otherwise actually mounted up no problem. My block also came with brass core plugs already.

 

[Rick Stephens]

I just did this with an '89 --> '01. My biggest issue was the harmonic balancer and the metric block. I ended up removing it and removing the CPS reluctor that's behind the timing cover. My water pump also wouldn't clear the composite timing cover, needed a new one.

The pulleys and brackets otherwise actually mounted up no problem. My block also came with brass core plugs already.

I would suggest going with a pre-vortec block and avoid all that unpleasantness.

 

[nola mike]

I would suggest going with a pre-vortec block and avoid all that unpleasantness.

They were tough to find in the yard, and I'm not sure when year the unpleasantness started. If I knew what parts I needed and didn't have to reinvent the wheel for every new problem it wouldn't have been *too* bad.

 

[Rick Stephens]

They were tough to find in the yard, and I'm not sure when year the unpleasantness started. If I knew what parts I needed and didn't have to reinvent the wheel for every new problem it wouldn't have been *too* bad.

Any 4.3 without a balance shaft would satisfy me.