Small Port Vortec head benefits over other heads?

[RobZ28]

We know the Vortec chamber is more efficient over say conventional open chamber heads, and that the ports are taller than the conventional SBC port… and that they are the best iron SBC head ever produced by the general.

When you start talking about racing, you can’t help but hear from numerous racers and engine builders how well these things work over other heads and if ported correctly how well they perform.

We know airflow doesn’t tell the whole story so what is it about Vortec heads that actually make the difference? Is it the port shape? Airspeeds in the right places? The chamber? All of the above? When going to an iron head on a SBC why do these heads always get the nod and usually outperform what’s on paper when compared to any other ported conventional head?

I know this is a newb question but I’ve never heard of specific reasons, just benefits which we know could very well be wives tales. Thank you!

[Tom68]

All of the above. Height, chamber shape, short turn, spark plug location.
Taller port gets rid of one velocity change point as long as you don't widen the entry.

[1980RS]

Yes, all of the above. When I was talking with the GMC rep just before the '96 trucks 350 SBC Vortec engine came out he told me about the new Vortec head. He was saying that they did have race technology in them and sure as hell do. Raised runners, fast burn chamber and made more power on less spark advance. I will say it's the best GM production SBC ever made. In 2019 I ran 10.90's@120mph on a 400 SBC with a set of Vortec's that used stock size valves, a little chamber work and some mild porting that did not inc. any of the intake port opening work done, like port matching. To me the a small port(185cc or 210cc) Vortec head will make even better power. It's just too bad GM made the prices on those heads go through the roof as what you would pay for a nice set of Vortecs could buy you some AFR's these days.

[RobZ28]

Yes, all of the above. When I was talking with the GMC rep just before the '96 trucks 350 SBC Vortec engine came out he told me about the new Vortec head. He was saying that they did have race technology in them and sure as hell do. Raised runners, fast burn chamber and made more power on less spark advance. I will say it's the best GM production SBC ever made. In 2019 I ran 10.90's@120mph on a 400 SBC with a set of Vortec's that used stock size valves, a little chamber work and some mild porting that did not inc. any of the intake port opening work done, like port matching. To me the a small port(185cc or 210cc) Vortec head will make even better power. It's just too bad GM made the prices on those heads go through the roof as what you would pay for a nice set of Vortecs could buy you some AFR's these days.

Thats pretty quick for some mild iron heads. No doubt. I have a really nice and original car that sits most of the time and I am interested in giving it a little more power than stock. My options are an AFR head, a Corvette L98 aluminum head, or a Vortec Small Port head. Any of them can have porting or what not... It basically comes down to what the best head for the real job is. Sitting, some cruising, SOME spirited driving but no real racing. I like the iron option for this... but Im sure others will disagree.

[Steve K]

I've got a hopped up 350 with Vortec heads and a dual quad set up in a big ol 83 Pontiac Parisienne 4 door and whatever GM did in the engineering on these head, they flat out work. Paid $200 for a set of used and all I did was a 3 angle valve job. Having said that, I had had a set of Vortec's and AFR's (say 195's) sitting on a bench to choose from I'd definitely go with the AFR's.

[skinny z]

or a Vortec Small Port head.

Or you talking about the original Vortec production head at 170cc? Casting number 10239906 or 12558062.
https://www.gmperformancemotor.com/parts/12691728.html

The reason I ask is because when I see the term "small port" mentioned, I immediately think of the GM P/N 19331470 advertised as "Small-Port Vortec Bowtie Cylinder Head Assembly".

https://www.gmperformancemotor.com/parts/19331470.html

There's a distinct difference between the two. 170cc vs 185.

[travis]

The one thing that sucks about the factory vortec's is that they are a lightweight casting, and have a bad tendency to crack for no apparent reason sometimes. Especially once they get some miles on them, or when they get overheated because of water loss from intake gasket failures.
With that said though, it never ceases to amaze me how well these L31's run even stock. We just stuck a stock high mileage one in my sons '94 GMC K1500, bone stock other than headers and a small dual exhaust system, a TBI conversion intake, and a reprogrammed chip. It runs amazing for something that idles dead smooth

[RobZ28]

I’m speaking of the small port 185’s specifically but all Vortec heads seem to have inherited these characteristics.

If this car didn’t sit most of the time and had higher hp goals I’d pick aluminum.

[skinny z]

I’m speaking of the small port 185’s specifically but all Vortec heads seem to have inherited these characteristics.

If this car didn’t sit most of the time and had higher hp goals I’d pick aluminum.

Aren't most of the success stories based around the L31 production casting? I had a set new from GM over twenty years ago and while not a dedicated racer as many are here, they were most certainly overachievers.

I believe this is the head 1980RS is referring in the quote below.

In 2019 I ran 10.90's@120mph on a 400 SBC with a set of Vortec's that used stock size valves, a little chamber work and some mild porting that did not inc. any of the intake port opening work done, like port matching.

[Justa1time]

I have a set of Engine Quest ch350C's on my 350 in my Nova. I will post some track times this spring when I take it out. I have looked and looked for a set of the RHS vortec castings but can't seem to find any. My engine quests are the castings from China. I learned that after I sourced them.

Cheers to Vortec heads.

[Tartilla]

I have a set of Engine Quest ch350C's on my 350 in my Nova. I will post some track times this spring when I take it out. I have looked and looked for a set of the RHS vortec castings but can't seem to find any. My engine quests are the castings from China. I learned that after I sourced them.

Cheers to Vortec heads.

RHS had a great thing going with their SBC heads. Not sure what happened.

RHS Vortec heads pop up now and again. Likely need a national search vs just local.

I put a pair of 1.94 valved RHS vortecs on my 355 boat engine. They really performed and were very efficient.

I wasn't happy with the intake sealing issues though.

[skinny z]

I've the 2.02 valved version of the RHS Vortecs.
And like posted above there doesn't seem to be a lot of info out there.
Had another valve job done and some pocket porting but otherwise as is.
255@.500". (4.03 fixture bore).
I've a new spec engine (357) to run this year and I'll see if I can't improve on trap speed.
XFI hydraulic roller. 274/282, 224/230, 110. .575".
Previous best was about 109 in a 3650 lb 3rd gen Camaro. Terrible 60' at 1.8-1.9.

[Tom68]

I wasn't happy with the intake sealing issues though.

Fixable.

20211228_113708.jpg

[1980RS]

I've the 2.02 valved version of the RHS Vortecs.
And like posted above there doesn't seem to be a lot of info out there.
Had another valve job done and some pocket porting but otherwise as is.
255@.500". (4.03 fixture bore).
I've a new spec engine (357) to run this year and I'll see if I can't improve on trap speed.
XFI hydraulic roller. 274/282, 224/230, 110. .575".
Previous best was about 109 in a 3650 lb 3rd gen Camaro. Terrible 60' at 1.8-1.9.

They are probably like the Pro-Topline Vortec's I had that were 2.02 and 1.6 and they flowed really well. Should not have sold them but the guy gave me more then double what I paid for the heads.

[1980RS]

I have a set of Engine Quest ch350C's on my 350 in my Nova. I will post some track times this spring when I take it out. I have looked and looked for a set of the RHS vortec castings but can't seem to find any. My engine quests are the castings from China. I learned that after I sourced them.

Cheers to Vortec heads.

RHS had a great thing going with their SBC heads. Not sure what happened.

RHS Vortec heads pop up now and again. Likely need a national search vs just local.

I put a pair of 1.94 valved RHS vortecs on my 355 boat engine. They really performed and were very efficient.

I wasn't happy with the intake sealing issues though.

Use the Felpro composite thick intake gaskets, sure fixed my leaky problems with those intakes.