Thread: head flow

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recently i just finished my vortec heads, but had some disappointing results with them.Car Craft did a test a while back with 355 and a LT4 Hotcam and a stock set of vortecs and made 420hp. then they took the heads and ported them out. I copied them exactly what they did to the vortecs and even added bigger valves on mine. there baseline was 228cfm intake @.500 and 152cfm exhaust@.500 after their porting they got 239cfm intake @.500 and 218cfm exhaust @ .500. then they bolted the heads on and ran another pull and got 460hp.
my baseline with bigger 2.02 vlave with no porting was 194cfm @ .550 and 163cfm exhaust @ .500. with 1.60 valve no porting.
I did my porting exactly to what they did, i blended the bowls in to 85 percent throat diameter.the valve guide bosses were narrowed, and the intake cross sectional area was opened to a .906 wide to a 1.100 wide. with a good gasket match with intake, exhaust ports. I brought my heads to a flow bench and heres my results with vortecs with 2.02 1.60 valves
intake Exhaust
.050 29 28
.100 65 58
.200 129 121
.300 180 169
.400 219 188
.500 224 201
.550 226 203
.600 227 204

these were supposebly flowed at 28 inches of h20. I want to know is the flow bench i used not accurate or is Car craft's numbers a bunch of bull****, has anyone ported a set of vortecs and flowed them in person or a stock set too?

Originally Posted by vortec king

recently i just finished my vortec heads, but had some disappointing results with them.Car Craft did a test a while back with 355 and a LT4 Hotcam and a stock set of vortecs and made 420hp. then they took the heads and ported them out. I copied them exactly what they did to the vortecs and even added bigger valves on mine. there baseline was 228cfm intake @.500 and 152cfm exhaust@.500 after their porting they got 239cfm intake @.500 and 218cfm exhaust @ .500. then they bolted the heads on and ran another pull and got 460hp.
my baseline with bigger 2.02 vlave with no porting was 194cfm @ .550 and 163cfm exhaust @ .500. with 1.60 valve no porting.
I did my porting exactly to what they did, i blended the bowls in to 85 percent throat diameter.the valve guide bosses were narrowed, and the intake cross sectional area was opened to a .906 wide to a 1.100 wide. with a good gasket match with intake, exhaust ports. I brought my heads to a flow bench and heres my results with vortecs with 2.02 1.60 valves
intake Exhaust
.050 29 28
.100 65 58
.200 129 121
.300 180 169
.400 219 188
.500 224 201
.550 226 203
.600 227 204

these were supposebly flowed at 28 inches of h20. I want to know is the flow bench i used not accurate or is Car craft's numbers a bunch of bull****, has anyone ported a set of vortecs and flowed them in person or a stock set too?

Well the good news is your intake to exhaust ratio is great at over 89%.
The bad news is your intake numbers are about like stock.
Due to casting "flash" and "core shift" there is alot of difference in production heads.
I.M.O.,the flow numbers will support 425 hp.
If you like n20 then these heads would work great.
If you are new to head porting don't be to up-set with yourself.
You can always sell the heads and start again.

Originally Posted by erik erikson

Well the good news is your intake to exhaust ratio is great at over 89%.
The bad news is your intake numbers are about like stock.
Due to casting "flash" and "core shift" there is alot of difference in production heads.
I.M.O.,the flow numbers will support 425 hp.
If you like n20 then these heads would work great.
If you are new to head porting don't be to up-set with yourself.
You can always sell the heads and start again.

on the flow bench i used they flowed a set of stock 062's and got 197cfm on the intake and 140?cfm on exhaust, the bench i used was a superflow 1020 and works well. I think those numbers that carcraft,chevyhiperformance,hotrod, and most cylinder head manufacturers post numbers a bit on the high side to possibly promote sales.or like what the other guy said every flow bench could be a bit different. if you go to car craft and go to the cylinder head database-under 170cc and smaller, the vortec head they listed flows 239cfm on intake, which in my opinion, is probably BS. i would like to take the head they flowed and flow it on my flow bench and see would the flow numbers really are, probably less than mine. have you guys ported a set of vortecs and flowed them?

Originally Posted by vortec king

on the flow bench i used they flowed a set of stock 062's and got 197cfm on the intake and 140?cfm on exhaust, the bench i used was a superflow 1020 and works well. I think those numbers that carcraft,chevyhiperformance,hotrod, and most cylinder head manufacturers post numbers a bit on the high side to possibly promote sales.or like what the other guy said every flow bench could be a bit different. if you go to car craft and go to the cylinder head database-under 170cc and smaller, the vortec head they listed flows 239cfm on intake, which in my opinion, is probably BS. i would like to take the head they flowed and flow it on my flow bench and see would the flow numbers really are, probably less than mine. have you guys ported a set of vortecs and flowed them?

Yes we have ported a set of Vortec's.
Most of the time out of the time from looking at my records I see with a 1.94/1.5 valve I see 215 to 220 at 28 inches of water and .500 lift.
Also keep in mind the valve design,valve job,combustion chamber work will effect these numbers also.
Yes, sometimes their numbers are a bit in-flated.
Even if you look at Scoggin Dickey parts catalog thet rate the L31 Vortec heads at 239/147, at .500 and 28" of H2O,that is a stock" out of the box "head .

My book shows the same on stock heads ....239/147 @.500 .....but shows the exaust at 160 with pipe @ .500.
All the articles I have read show almost 20 cfm improvement from work to the valve ,with a special back cut, and seat work.But all the articles state keep away from the intake runner if unsure what to exactly do,because with a bigger valve you have to keep the high swirl going.......if not the flow will go down.Most of them say stay away from the short side radius if unsure as it will decrease flow from just opening this up full size on the vortecs.
Can you post some pics and do the valves have back cuts ,if so what are the angles on the back cut and are there 4 cuts or 3?Did they install massive hd seats for the bigger valves or cut down the existing seats ?Did they use oversized valves and hone the guides or install new guides?Whats the stem difference from stock valves to the new valves?Did you flow more than 1 runner on the intake?
I am with Erik those heads would love n2o or a some forced induction the way they are!!!

here is the pics of my vortecs, the heads have been cut out for 2.02/1.60 valves, I blended the bowls, narrowed the valve guide boss on intake and exhaust. I did not remove any material on the short turn radius, just remove slight ridege. the valves are ferrea stainless steel valves with back cuts on both intake and exhaust. The valve seats have a three angle valve job done on them, i don't remember the angles.

Originally Posted by vortec king

here is the pics of my vortecs, the heads have been cut out for 2.02/1.60 valves, I blended the bowls, narrowed the valve guide boss on intake and exhaust. I did not remove any material on the short turn radius, just remove slight ridege. the valves are ferrea stainless steel valves with back cuts on both intake and exhaust. The valve seats have a three angle valve job done on them, i don't remember the angles.

Don't take this the wrong way but you are only half way done with the heads.
The good thing is you did not touch the short turn radius.
After looking at the pictures I see a lot of tooling marks.
To pick up flow on the intake side you need to go back and do more work in the guide area.
Remove a lot more material on the area where the valve starts to go into the guide.
Also on either side of it the guide in the "roof area" directly opposite of the short turn radius.
In your combustion chamber you need to really work on the spark-plug "boss area" radius any and all sharp lines.
I want you to look at this web site www.e-squared-engineering.com
I am not trying to sell you anything just help you and give you ideas.

Originally Posted by erik erikson

Don't take this the wrong way but you are only half way done with the heads.
The good thing is you did not touch the short turn radius.
After looking at the pictures I see a lot of tooling marks.
To pick up flow on the intake side you need to go back and do more work in the guide area.
Remove a lot more material on the area where the valve starts to go into the guide.
Also on either side of it the guide in the "roof area" directly opposite of the short turn radius.
In your combustion chamber you need to really work on the spark-plug "boss area" radius any and all sharp lines.
I want you to look at this web site www.e-squared-engineering.com
I am not trying to sell you anything just help you and give you ideas.

i've been working on my heads and the valve guide area is really shaping up, to give you an idea there is about 1/16 of material around the valve guide hole.I'll post more pics later on. I'm assuming that there could be valve shrouding in the combustion chamber with the big valves. that was one step i didn't do that car craft did, I'm some what hesitate about combustion chamber work, because it's very time consuming, but i'll do it if increases the flow. Also i was thinking having a company called R&R performance in the twin cities take a look at the heads. these guys are incredible! there was this guy who built a 400 pontiac in my town, new comp cams,intake,headers,good carb, etc. the engine dynoed at 367hp and 411tq. the guy pulled the heads off and sent them to R&R performance and they did a complete port job and possibly bigger valves. the guy assemble the engine with nothing more than before. the engine made another 100hp! no bull**** that's amazing!!! Obivously they won't be able to get that with vortecs, because they're so good to begin with, but they would be able to more flow out of my heads than i would. I doubt i will allow them to port the heads, assuming they'll charge close to 800 to 1000 dollars, i just want to see what they recommend for valve seat angles, combustion deshrouding, possibly opening the port up bigger. erik, where exactly do i need to work the combustion chamber? and also this out of the blue, but do you ever go to the drag strip in humbolt?

Originally Posted by vortec king

i've been working on my heads and the valve guide area is really shaping up, to give you an idea there is about 1/16 of material around the valve guide hole.I'll post more pics later on. I'm assuming that there could be valve shrouding in the combustion chamber with the big valves. that was one step i didn't do that car craft did, I'm some what hesitate about combustion chamber work, because it's very time consuming, but i'll do it if increases the flow. Also i was thinking having a company called R&R performance in the twin cities take a look at the heads. these guys are incredible! there was this guy who built a 400 pontiac in my town, new comp cams,intake,headers,good carb, etc. the engine dynoed at 367hp and 411tq. the guy pulled the heads off and sent them to R&R performance and they did a complete port job and possibly bigger valves. the guy assemble the engine with nothing more than before. the engine made another 100hp! no bull**** that's amazing!!! Obivously they won't be able to get that with vortecs, because they're so good to begin with, but they would be able to more flow out of my heads than i would. I doubt i will allow them to port the heads, assuming they'll charge close to 800 to 1000 dollars, i just want to see what they recommend for valve seat angles, combustion deshrouding, possibly opening the port up bigger. erik, where exactly do i need to work the combustion chamber? and also this out of the blue, but do you ever go to the drag strip in humbolt?

Work where you have the right arrow.
Look at as if it where a clock.
Un-shroud in the area from 1-4.
Have your head gasket ready so you won't go to far.
Yes,I have been to the drag-strip at Humbolt but it was back in the early 90's.
The only people I still know up ther is "Grove Brothers racing".
They have an Opal GT with BBC in it.