vortec heads on 350

[1983ChevyK30]

i got a 1980 chevy k30 that i use mostly as a work horse. i do a lot of pulling with the truck and the power department needs great improvement. motor is completely stock besides headers. i would love to do the vortec head swap before im done with hs and off to college and dont have time for this stuff. im kinda new to swapping heads and figuring out what size cam to use and figuring out quench area etc. (im more of a snowmobile modifier). but i am very mechanically inclined and have tools to do this job. i would love to put a little bigger cam in it but im not 100% sure on how to figure out what size cam and how much lift. can i use stock push rods? i plan to keep short-block stock it has the LT9 350. Just want to do top end. i want this truck to run off of 89 pump gas. not looking to build a race motor just a good pulling torque motor. any help on how to go about swapping the heads and caming up would greatly be appreciated. thanks

 

[Ronno6]

What RPM range do you need?
For gobs of low end torque, the dreaded "swirl port" heads do a great job and are usually available for cheap, but they somewhat choke things off above 4000 or so.
Swirl ports do a great job throughout the power band, I believe, but, if you opt to go with them. either purchase new or have magnafluxed prior to purchase, as they are notorious for cracking.
My machine shop man said that 8 out of 10 Vortecs he gets in are cracked. I took a pair in myself, and both were cracked.
Vortecs also limit your cam selection, unless modified.
Read up on them, as I cannot remember the exact limitations, but I believe that it is in the .450 range without changing springs,etc.

 

[1983ChevyK30]

i would be in the 650-4500 rpm range.

 

[SquareRoot]

I recently put vortecs ($700/pair from Summit) on my LT9 engine (85 k20) along with a mild comp cam (XE 256). Lift is around.450 so no problem with stock valve springs. Along with long tube headers and a Edelbrock 1406 carb it runs really strong. You'll need a new intake manifold as well to fit the vortecs.

 

[4WDKC]

What RPM range do you need?
For gobs of low end torque, the dreaded "swirl port" heads do a great job and are usually available for cheap, but they somewhat choke things off above 4000 or so.
Swirl ports do a great job throughout the power band, I believe, but, if you opt to go with them. either purchase new or have magnafluxed prior to purchase, as they are notorious for cracking.
My machine shop man said that 8 out of 10 Vortecs he gets in are cracked. I took a pair in myself, and both were cracked.
Vortecs also limit your cam selection, unless modified.
Read up on them, as I cannot remember the exact limitations, but I believe that it is in the .450 range without changing springs,etc.

Mine wouldnt pull worth a damn past 3k with the stock tiny cam in it.

I recently put vortecs ($700/pair from Summit) on my LT9 engine (85 k20) along with a mild comp cam (XE 256). Lift is around.450 so no problem with stock valve springs. Along with long tube headers and a Edelbrock 1406 carb it runs really strong. You'll need a new intake manifold as well to fit the vortecs.

^This at a minimum or dont bother. By the time you pay for the heads, having them checked for cracks, valve job, seals, expensive retainers and locks, special springs you are at the cost of new iron heads, then you need specific intake to match, modify brackets to work with new intake. All in for the vortec heads and cam swap I did on my truck it was close to $1000.. wish I had either swapped in a ls or my 454 for that much money.

 

[SquareRoot]

Yep. I'll never build another traditional sbc. LS or go home. Only reason I did it this time was because the PO just put a brand new crate 350 in it and I already had a complete serpentine system to swap. I hated buying flat lifters for the cam swap but I didn't want to go down the rabbit hole without a fight.

 

[1983ChevyK30]

i do have a 454 bbc with 781 heads that i could swap in there

 

[Paladin]

i do have a 454 bbc with 781 heads that i could swap in there

So what are you waiting for? Git er done!

 

[rpcraft]

There are some ebay vortec Aluminum heads I have been reading that are on ebay, not sure of the brand or seller, but from all accounts they are affordable and decent but not sure on exact numbers. I heard it discussed on this video but can not recall the details and don't have the time to go back and watch it...

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[75gmck25]

I considered a Vortec head swap, but also wanted to make sure they would handle higher lift and a roller cam. After determining what I would have to spend for Vortec's set up to to handle more spring pressure and higher lift, I decided to buy Blueprint H8002k aluminum heads instead.

Blueprint H8002k heads were $899 from Summit, but the only additional items I needed for the heads was the gaskets and new head bolts. They are drilled for both Vortec intake and the older intake, and they can use center bolt or perimeter valve covers, so you don't have to replace those items.

I also used a retrofit roller cam, so that added quite a bit to the cost, but I think its worth it in the long run.

Bruce

 

[1983ChevyK30]

will the bell housings bolt up? are the clutches the same? 454 is out of a late 70s truck. at least that is what the guy i bought it from told me. the engine is not blue it is orange. are these motors internally balanced? i would cam it up and go through it before i put it in. would it be advantageous to deck block to bring up compression?

 

[WFO]

They are externally balanced from the factory, but can be made internal by adding weight to the crank.

 

[77 K20]

Keep in mind the one disadvantage no one ever talks about with vortec heads... COLD WEATHER!!!

Vortec heads and the intake manifold got rid of the exhaust heat crossover tube that is below the carb. This was removed as vortecs moved the fuel injectors to closer to the valves. They wanted to make the intake as cold as possible for more power with denser air coming into the engine.

Now if you live in a cold climate and run a carb fuel likes to drop out of suspension when it suddenly changes direction. What you end up with is puddling of fuel right under your carb. GM makes a intake manifold for vortec heads and a carb but there is not "waffle pattern" under the carb. A waffle pattern or ridges along the plenum there help get fuel airborn again. Fuel can rise up to the top of a ridge and then lets go and flies on down to a cylinder. Kinda helps a bit.

At temps of about 40 degrees or below I noticed that I had a miss and the engine couldn't run quite right. It can take a long time to heat soak the intake enough for it to start running right (I have a 10 minute drive on the highway doing 65 and at the first stop light it would still run like crap).

I bought an edelbrock intake manifold that has a externally plumbed heat passage in it. It runs coolant thru it. Still runs like crap when cold, but will warm up much faster. BUT: when I installed my first manifold I went thru a lot of coolant. Every time the engine heated and cooled it would drink coolant. I found small PUDDLES of coolant inside the plenum. Edelbrock refused to believe me even with pictures. I replaced with a SECOND intake manifold and the SAME thing happened. I was so pissed at that point I added a tube of alumniseal and dropped my radiator cap from something like a 14 psi one to a 7 psi cap. Haven't used a drop of coolant since. Perhaps it would be possible to pipe exhaust thru that plenum instead...

And lastly, they say vortec heads need an external coolant bypass otherwise you get hot spots and boiling. With the GM manifold I didn't do the bypass and could watch my coolant gauge go from 180 to 215 and back to 180 every 20 seconds or so on the highway. Replacing the thermostat did nothing. Plumbing up the heat passage worked as a coolant bypass and then evened the temperature right out.

 

[shiftpro]

Keep in mind the one disadvantage no one ever talks about with vortec heads... COLD WEATHER!!!

Vortec heads and the intake manifold got rid of the exhaust heat crossover tube that is below the carb. This was removed as vortecs moved the fuel injectors to closer to the valves. They wanted to make the intake as cold as possible for more power with denser air coming into the engine.

Now if you live in a cold climate and run a carb fuel likes to drop out of suspension when it suddenly changes direction. What you end up with is puddling of fuel right under your carb. GM makes a intake manifold for vortec heads and a carb but there is not "waffle pattern" under the carb. A waffle pattern or ridges along the plenum there help get fuel airborn again. Fuel can rise up to the top of a ridge and then lets go and flies on down to a cylinder. Kinda helps a bit.

At temps of about 40 degrees or below I noticed that I had a miss and the engine couldn't run quite right. It can take a long time to heat soak the intake enough for it to start running right (I have a 10 minute drive on the highway doing 65 and at the first stop light it would still run like crap).

I bought an edelbrock intake manifold that has a externally plumbed heat passage in it. It runs coolant thru it. Still runs like crap when cold, but will warm up much faster. BUT: when I installed my first manifold I went thru a lot of coolant. Every time the engine heated and cooled it would drink coolant. I found small PUDDLES of coolant inside the plenum. Edelbrock refused to believe me even with pictures. I replaced with a SECOND intake manifold and the SAME thing happened. I was so pissed at that point I added a tube of alumniseal and dropped my radiator cap from something like a 14 psi one to a 7 psi cap. Haven't used a drop of coolant since. Perhaps it would be possible to pipe exhaust thru that plenum instead...

And lastly, they say vortec heads need an external coolant bypass otherwise you get hot spots and boiling. With the GM manifold I didn't do the bypass and could watch my coolant gauge go from 180 to 215 and back to 180 every 20 seconds or so on the highway. Replacing the thermostat did nothing. Plumbing up the heat passage worked as a coolant bypass and then evened the temperature right out.

Thanks for the great post Mike.
Again another advantage of propane btw. This gas never drops out of suspension and thus you can use a tunnel ram on the street with no problems, just saying.
Back to the Great Vortec heads, instant 40 hp.... probably best to go with aftermarket at the end of the day, and gain 50 hp.

 

[DirtyDYT]

i do have a 454 bbc with 781 heads that i could swap in there

Do that. You won’t regret it. I hit 4th gear at 20 mph around town in my 454 K30 and it still pulls up hills.

will the bell housings bolt up? are the clutches the same? 454 is out of a late 70s truck. at least that is what the guy i bought it from told me. the engine is not blue it is orange. are these motors internally balanced? i would cam it up and go through it before i put it in. would it be advantageous to deck block to bring up compression?

The bell housing should bolt right up. You should even be able to reuse the frame size engine mounts and the engine side clamshells. Not sure if the clutch is the same. If you do swap it you may as well install a new one for a big block truck.

I won’t discourage you from building it up a bit but even the stock low compression 454’s pull great.