Vortec's - How to Kill Flow and How to Increase it! Vortec Head Exhaust Flow

Theres alot of talk and questions about exhaust flow on Vortec heads. Hopefully this video helps answer some of those questions and provides some answers on how to increase flow when home porting your Vortec exhaust ports. Watch in HD 1080 to see charts easier
Heads flowed at 28hg, 4.030 bore with No Pipe
This video is educational (not a how to port video) and I can only provide information and results from my own experiences and flow tests. I am not responsible for any damage from others trying to port their own cylinder heads.
Please comment below if you have any questions
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[@eddiecahall3824]

Nice review. Here's what I know what professional designers from GM say about performance with the Vortec cylinder head. You don't mess with the intake ports, only just get rid of sharp edges only. They flow already like a decent small race port head! Up to 525 max lift. On the exhaust ports, they leave a little more to be desired,and can be ported for a 67cc size or so flow. that's it! The cylinder heads will produce up to 500 HP+ w the right compression and build! All with astronomical torque w a dual lift and split duration camshaft in a small roller! Check it out no BS! I been doing this over 30 yrs.

[@oldsrocket8456]

I hear you brother

[@patrickwendling6759]

Thank you for your knowledge and videos

[@mikkokuorttinen3113]

Great video Pat, keep it up! Can't wait for the video about the intake port

[@davidreed6070]

Be careful cutting the back of the ex valve you will gain flow but cause reversion that cannot be measured on the bench

[@msh6865]

How much hp/torque increase over stock would you expect to see with just the 1.6 ported exhausts?

[@cuttersperformance]

Too many variables to say. But anything ive dynoed always seems to make more power with better exhaust flow (single pattern or dual pattern cams) but ive never done a back to back on the same engine to say an exact amount

[@jimjohnson3357]

When you put in the 1.6 valve and did the port, what angles did you put on the valve? 30? 15? none?

[@cuttersperformance]

No back cut on the exhaust valve

[@jimjohnson3357]

Thanks

[@ralphparker9263]

Sure like those Vortech heads!!

[@sarsavage]

I have the EQ vortec heads will I kill it to go up to the 202,& 160 valves am into street /strip 150 shot of nitrous

[@cuttersperformance]

They have more meat to port for the 2.02 valve. I find the stock oe castings get quite thin if bust through if you try to utilize the 2.02 valve on the intake but the EQ castings are thicker. The 1.6 valve will be a benefit woth porting especially with nitrous

[@reason2gether]

Excellent video! After grinding the cast iron, what method do you use to clean out the shavings? Bath in parts-cleaner or just blow out with compressed air?

[@cuttersperformance]

Shop vac, blow gun, parts washer then brake clean and blow gun till dry

[@reason2gether]

@@cuttersperformance Yeah. The iron filings tend to magnetize and make it hard to get out. Same here. Thank you for replying. Have a safe and happy 4th myfriend. God Bless.

[@born2wrench]

How do I know if I have a mexican casting. Also 480 lift cam work without doing any machine work on the head

[@baims8367]

Modern day VIZARD 💪🏻👍🏻🏁

[@itseithergonnaworkoritaint7852]

Great info, thanks for sharing.

[@cuttersperformance]

Thanks man appreciate it

[@peterluta1119]

Hi Pat!! Is there a chance you can do a test on the intake side. Using a your porting and unshrouding the valve with a 2.05 intake valve

[@timothyesmond7358]

Great info

[@chrisd078]

Summit Racing just came out with a series of sbc cams with an LS firing order. Curious to see if they run good?

[@kyleoden7656]

Why dont you redo the 2.02 valves but deshroud them and port them in steps like you done the exhaust in this video and see what kind of difference it makes

[@charlierhiger7478]

I have a set of camel back heads that have 2.05 valves with longer valves and 5 angle valve job . I have no idea what the flow on those are the guy that built them did not have a dino to give me numbers but it is a very very strong engine. Would I be able to get better numbers from a 906 vortex set of heads?

[@georgesam7805]

I like the vortecs for a cheap iron head too. Can you post a video of you flowing them compared to other iron heads and any port work you'd do on them ? What do you use to cut valve seats? Thanks

[@charlierhiger7478]

I am totally lost when it comes to flow numbers as far as what is good and what is bad. Can I get help with that?

[@shepsplasticbodyshop]

saw you on Nick's Garage...here to be impressed

[@rickyfulks889]

Considering the high pressures the exhaust port has on a running engine, how much can a flow bench really represent as good data?

[@davidreed6070]

Right not much just as a guide

[@konnerkramer329]

Definitely true buy dynos don't lie. A flow bench will give you a judge of the quality of porting. If you touch up a few edges and radius the bowl and gain 20cfm you know your doing OK. But if you port the fuck out of the exhaust and remove half a pound of cast iron and gain 20cfm you know you fucked up

[@cuttersperformance]

Agreed its just a guide but good exhaust flow has always helped and made more power with anything I've dynoed. Even intake flow on a bench is a guide in my opinion

[@rickyfulks889]

@@cuttersperformance yeah, definitely the intake. Thats the real power

[@konnerkramer329]

@rickyfulks889 gotta get the air out somehow. I think a lot of people are surprised how much power a bad exhaust can kill. I've seen upwards of 80hp on a BBC

[@jesseduke694]

I believe it was Eric Wingardner I heard say this?? I could be mistaken??? But back cutting the exhoust valve gains flow but becouse of reversion it will loose power. I've never tested so.....? I'm only repeating what I've heard. So take that for what it's worth.

[@cuttersperformance]

I may have explained it poorly in the video but the valve mod isnt to add a back cut to the factory valve but to smooth the factory cast lip on the back side of the valve using a valve grinder machine at 15 deg to make it more like a aftermarket valve. But a normal back cut is added to a valve (usually 30 deg) to aid in low lift flow, but rarely do you see a back cut on an exhaust valve because of the fear of reversion. I have tried 30 deg backcuts on exhauat valves on the flow bench just to see the results, but have never done a back to back dynoed test to see what it would do to power/reversion, but it would be quite interesting to try. The issue though, would be that it would really depend on combination, cam, headers and even exhaust system ect

[@jesseduke694]

@piss-cutterperformance right, I agree. My comment was aimed more toward question 2, when u answered that question. You did mention reversion. I understand what u were saying about taking the edge or the lip off & putting a lil 15 angle on it.

[@Classickoolcars]

@@cuttersperformance surely reversion isn’t an issue if you run long tube headers? Only stock manifolds? Cheers and keep up the great work 👍👍. Loving your posts.

[@zAvAvAz]

👌

[@100amps]

What a great video. Keep 'em coming!

[@joe212]

Can i squeeze a 5cc dome pistion in with 062 vortec heads

[@cuttersperformance]

Yeah you can run them but often times youll have to clearance the square notch in the combustion chamber on the vortec head. The one near the spark plug. If you look back to my dingle ball 355 videos I believe I show that

[@joe212]

@@cuttersperformance thanks

[@joe212]

@@cuttersperformance looking for it maybe i missed it tho

[@darthvader3618]

I hope someone can help with this question. I’m building an 89 corvette L98 engine can I use a vortec head on L98 and get better flow than the stock heads? Or would it be better to get the stock heads worked on?

[@earlbrown]

Vortec heads are far superior than the L98s you have now. The main issue you're going to have is the TPI intake won't bolt up to the Vortecs.

[@darthvader3618]

@@earlbrown thanks for taking the time to reply to my question.

[@stevenbelue5496]

What good is a bigger door if you don't open the door jamb up

[@cuttersperformance]

Exactly

[@Classickoolcars]

Makes sense right 🤷‍♂️👍

[@plumcrazy588]

Great video as usual...I do have a question on why you stopped the throat % at 85%? Does the exhaust flow suffer with a bigger throat like a 88-90%?

[@cuttersperformance]

I tell guys to shoot for 85% for a few reasons. 85 to 90% range your looking for good flow, But typically when I tell a someone to open it up to 89% and ends up 92+% and often times into the valve job. 85% is a safe number to shoot for to allow for some error and final clean up. Over porting is easy to do, and it's not reversible. Shoot for 85% and you'll get 95% of the results without wrecking a head

[@evanm3209]

​@@cuttersperformance, when you're measuring your 85% throat ratio, are you using the valve head diameter, or the inside of the valve seat as your reference? Thanks very much for the great video.

[@robtdougherty]

@@evanm3209 - yes this. I think different people reference different. also, is that including the stem area or not.

[@robertbass974]

Are you doing this on budget L31?

[@cuttersperformance]

The budget L31 is just ported (no larger valve) to stick with the budget. Its shown in video on the final graph in blue vs stock and the 1.6 valve ported

[@mauricelively6937]

Hello Pat, how does on contact you for work?

[@cuttersperformance]

[e-mail]

[@lancecolby7792]

Hey Pisscutter! I gotta ask cause so far your the only one who talks about them, the 520 casting, do you think it’d outflow the vortecs? Cause David Vizard said that the heart shaped chamber basically creates a reversion and the air goes out the wrong way in basic terms so I was wondering with the same valve and same port work do you think they’d put flow the vortecs if the port is the same?

[@cuttersperformance]

Your referring to the 305 vortec heads (520 casting)?

[@lancecolby7792]

@@cuttersperformance yes sorry! I’ve always been super interested in them, because they have the same port size just smaller valve right

[@cuttersperformance]

@lancecolby7792 yeah thats correct. If you put in a larger valve they would flow almost the same as the 350 vortecs

[@lancecolby7792]

So that brings up another question if it flows the same with the same valve would it flow more with a 2.02 valve?

[@cuttersperformance]

@lancecolby7792 the problem is there's barely enough meat in the stock casting to port the head to ulilize the flow 2.02 valve. If there was more room for porting, then yes, you can get more flow with a larger valve. But the 1.94 valve works pretty well for a 170cc ish runner especially compared to other heads

[@georgesam7805]

What are you flowing these on ?

[@cuttersperformance]

I use a Superflow SF600 or a Flow Performance bench. Both benches are calibrated and identical results (within 1%)

[@terrymc70]

I have a set of world products sportsman ll heads and what do you suggest to do to them?

[@davidreed6070]

Those sportsman heads will make power in the right hands that is for sure. They do need work they shouldn't be put on in stock form

[@terrymc70]

@@davidreed6070 i want to learn how to port not on those but I have a few sets of stock sbc heads to learn on. I do know that bigger ain't always better.

[@timothyesmond7358]

Have you ever tried The Chinese version of the vortec Head?

[@cuttersperformance]

I have not yet. I've been getting a lot of guys asking about the promaxx ones lately

[@timothyesmond7358]

@@cuttersperformance I've bought several speedmaster ones. I had them flowed by Eric weingarter racing they didn't flow too good straight out of box. There's tons of metal in the casting though. And they don't crack I run them and demolition derbies and they seem to do just fine.

[@mediumjumbo7484]

The chart at 13:30. Whats the percentage of flow on that 1.6" valve, plus porting ,compared to an untouched intake port ? Above 75% ? 80% ?

[@cuttersperformance]

Depends on how you calculate it, but let's say at .500 lift it would be about 73%

[@mediumjumbo7484]

​@@cuttersperformance 👍 Thanks ! Enjoyed seeing you and Nick working together.

[@TheProchargedmopar]

👍💪

[@fukemallgarage]

Great stuff Cutter. Thanks for all the great info, happy 4th. Stay cool

[@cuttersperformance]

You to! Thank you