ANYONE USED VORTEC HIGH SWIRL HEADS ON THEIR GEN-I SBC?

I'm getting ready to build a 350ci. But I've got a fresh from the machine shop heads with beehive springs. Pulled them out of the iron scrap pile at the place I work. Guy said he had to move and had no place to put his car parts. He scrapped out those heads, a fresh Vortec block (which I don't have) and 3 other complete engines and a bunch of parts. Have an early sb Vortec marine engine. BUT! This block might end up being ****. I started tearing it down, and the first head bolt I twisted,.....twisted. OFF! Looks like someone probably had their boat in salt water and never rinsed it out. Good crank, from what I can see this thing has very low hours on it. Out of the countless SBC I've overhauled and work I've done on them over 40+ years, this is the very first head bolt I ever broke off. So might need to find another block. Got the expansion plugs out (they are NOT "freeze" plugs) and the engine turned upside down on the stand soaking in DEEP CREEP penetrating oil. But this thing is a standard RH turn water pump unit. Has the cast iron Quadrajet intake.I know some things have to be done to use thiose heads on a ver one block. So was just wondering if anyone has done that swap.

IIRC to run the Vortec heads you would need an intake manifold and because Vortec water pump uses a bypass hose a small hole needs to be drilled in the thermostat if you run a classic water pump.

Vortec block may or may not have the hole for a mechanical fuel pump rod machined. If you plan on using a mechanical pump that’s the first thing I’d look at on a Vortec block.

There should be a ton of information around about swapping to Vortec heads it was super popular in the late 90’s early 2000’s for an affordable 20-30 hp.

Are you sure about exactly what you have? Vortec heads and swirl are usually not used in the same sentence (although the Vortec port may have a swirl).

Swirl port was an older head design, but Vortec heads were used about 1996-2000 on the L31 SBC roller block.

Yep I have and still am. I wouldn't do it again.

Yep. As @SquareRoot said, wouldn't do it again.

There are several brands of inexpensive aluminum heads available for small blocks. Some complete sets are as cheap as $1000. It is easy to spend 4-500 rebuilding an OEM pair and that's if they aren't cracked. Looking back I should have done that on my last project.

They were the best factory head for the OG SBC. For the right money I would definitely use a set. They were covered extensively by car mags in the late 90s and early aughts, so there is a ton of info out there. The biggest draw back is the intake requirements at this point..

SquareRoot said:

Yep I have and still am. I wouldn't do it again.

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Just wondering why?

What were the negatives of the swap?

1STLS1 said:

Just wondering why?

What were the negatives of the swap?

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Aftermarket manifolds are limited, expensive and suck with a carburetor because they have no heat crossover. The heads are heavy and have limited spring clearance, around .450 lift I believe. They are prone to cracking and the water pump bypass is required. At the time they were made, they were good on TBI engines. Now, there are better, lighter and cheaper heads available.

SquareRoot said:

Aftermarket manifolds are limited, expensive and suck with a carburetor because they have no heat crossover. The heads are heavy and have limited spring clearance, around .450 lift I believe. They are prone to cracking and the water pump bypass is required. At the time they were made, they were good on TBI engines. Now, there are better, lighter and cheaper heads available.

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I'm just quoting this to bring up other points I made in a thread a while back. Plus a couple other things we may not have discussed before.

Lots of aftermarket performance heads designed for people using carburetors do not have a heat crossover, the vortec heads are no different in that regard.

The heads themselves have nothing to do with the water pump bypass. That's only an issue when using a vortec pump on a non-vortec block, or a non-vortec pump on a vortec block.

Yes, they are prone to cracking. BUT, it hardly ever causes any issues at all due to the location. I'd wager that 50% of the millions of vortec 350's driving around have or have had a cracked head and nobody knew it because they never tore the engine down and had them magnafluxed.


Personally, I would, and I do run them with a carb. I have two already. I have a set of vortec heads that are slated for use on another carb small block. Plus I have a few other carb small blocks with no heat crossover. One of them was even my daily driver in the winter.

75gmck25 said:

Are you sure about exactly what you have? Vortec heads and swirl are usually not used in the same sentence (although the Vortec port may have a swirl).

Swirl port was an older head design, but Vortec heads were used about 1996-2000 on the L31 SBC roller block.

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I forgot to quote this one too, for importance. The old TBI heads were commonly known as swirl port heads. They used center bolt valve covers, like the vortec heads. A lot of people think that all heads with center bolt valve covers are vortec heads.

And the lift limitations are easy to fix with Comp 787 retainers and 648 locks. LS6 beehives spring or their replacements Comp 915, 918. GM does the same on the 604 crates.


Or Alex's parts drop in kits. He's got 3 depending on cam

I wouldn't buy a new set for the price but if I had them already I would use them. No machining on these and good for .530 lift.

I was thinking it's the 062 vortec heads that dont crack as easily anyways, whatever the other ones are , those are the ones that crack

Secondly, with the 64cc chamber size, you'll have decent compression as is,

That said, much more than a .500 lift isnt really needed ?

The mentality of opening the valves as much as humanly possibly is kinda outdated when you can make good power with moderate lift and high compression... especially if its a daily driver
Keep your engine vacuum, have power brakes and have good power.

Just my opinion on that

Overlap (duration+LSA) has the most affect on vacuum and idle quality than lift. Just an example but my daily has the LT4 hotcam and has 15" of vacuum at an 800 RPM idle.

Kind of off topic but if you're gonna leave the tiny stock cam in there don't expect much from heads alone. Depends on how much driving you do (or don't in some people's cases) and what you use the truck for.

bucket said:

Personally, I would, and I do run them with a carb. I have two already. I have a set of vortec heads that are slated for use on another carb small block. Plus I have a few other carb small blocks with no heat crossover. One of them was even my daily driver in the winter.

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This really baffles me. My vortec head HT383 was basically undrivable in winter for the first 20+ minutes or so of driving. So much fuel puddled up in the cold intake manifold. That would then lead to the spark plugs clogging up.

But so it went when I did research on anything with my truck. 1/2 said no coolant bypass is needed. 1/2 said they have to have a coolant bypass and it the same thing with doing a rear brake disc conversion (works perfect vs you are gonna die).