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Discussion Starter · #1 ·
I would like to compare flow cure on a set of 290 BB Chevy heads that I'm working on. I'm now cc ing stuff just to see how much more the port volumes and chambers increased. I'm very happy with the flow curve/results, but would like to improve the bad port number's if possible with out welding. I ended up getting 325.8 c.f.m. @ .700 lift on the good intake port, and 292.58 c.f.m. @ .700 lift on the bad port with a clay radius. The exhaust was 243.0 @ .750 lift with no pipe. All numbers were at 28"s on a Superflow 120 and a 4.5 bore fixture.


Valve size : 2.190 with 3/8's dia steam 30 deg back cut, 3 angles on the seat cut with a cutter.
Number 1 intake port (Good Port)**Number 3 intake port (Bad Port)
.200 150.68******************.200 151.54
.300 215.36******************.300 161.52
.400 263.80******************.400 259.0
.500 287.78******************.500 274.99
.600 311.76******************.600 292.58
.700 325.83******************.700 290.98
.750 stalled******************.750 dropped off big time

Valve size : 1.88 with 3/8's dia steam 30 deg back cut, 3 angles on the seat with a cutter, the bottom cut being a radius into the seat
Number 1 Exhaust port (No pipe)
.200 129.76
.300 156.98
.400 191.16
.500 215.36
.600 239.86
.700 243.02

Chambers CC at 98.2, heads were milled .030.

I know the numbers will be better with the 4.5 dia bore fixture than a 4.280. But how much less will the numbers be. I would like too hear any thing good or bad about my heads. Willing too share what ever details needed about my heads. I have nothing too hide or prove or trying to take work away from any one. Just doing stuff for my self and wanting to learn from some of the good head Porter's that read this board, thats if they are willing too share. What can be done to get the bad port to flow a little more closer to the good port with in 10 to 15 c.f.m. With basic grinding or even adding some Epoxy to the ports to reshape it a way to create a little buffer to help the air move better into the chamber(bore), or create a different short turn in that port. Is that spread (Flow difference) that common on the BB Chevy iron oval port heads. I know the good port has a better natural path for the air to flow into the chamber (Bore) from left to right. The bad port makes a hard right turn into the right side of the chamber (Bore) and then probably dead ends their. I'm all ears on this, so grind (Fire) away.

Thanks for Looking and any info you are willing too share,

Ron Miller 92Camaro:beers:
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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you have your own flow bench?
 

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Discussion Starter · #4 ·
Tom, answer to you're question, No. I do have excess to the bench listed any time I need to use it.

Jason, No I do not at this time, but can take some when I'm completely done. I would like to get the bad port 10 to 15 c.f.m. closer to the good port with out welding. Do you have any info you are willing too share on the bad port fix ?

Ron Miller 92Camaro :beers:
 

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I would like to compare flow cure on a set of 290 BB Chevy heads that I'm working on. I'm now cc ing stuff just to see how much more the port volumes and chambers increased. I'm very happy with the flow curve/results, but would like to improve the bad port number's if possible with out welding. I ended up getting 325.8 c.f.m. @ .700 lift on the good intake port, and 292.58 c.f.m. @ .700 lift on the bad port with a clay radius. The exhaust was 243.0 @ .750 lift with no pipe. All numbers were at 28"s on a Superflow 120 and a 4.5 bore fixture.


Valve size : 2.190 with 3/8's dia steam 30 deg back cut, 3 angles on the seat cut with a cutter.
Number 1 intake port (Good Port)**Number 3 intake port (Bad Port)
.200 150.68******************.200 151.54
.300 215.36******************.300 161.52
.400 263.80******************.400 259.0
.500 287.78******************.500 274.99
.600 311.76******************.600 292.58
.700 325.83******************.700 290.98
.750 stalled******************.750 dropped off big time

Valve size : 1.88 with 3/8's dia steam 30 deg back cut, 3 angles on the seat with a cutter, the bottom cut being a radius into the seat
Number 1 Exhaust port (No pipe)
.200 129.76
.300 156.98
.400 191.16
.500 215.36
.600 239.86
.700 243.02

Chambers CC at 98.2, heads were milled .030.

I know the numbers will be better with the 4.5 dia bore fixture than a 4.280. But how much less will the numbers be. I would like too hear any thing good or bad about my heads. Willing too share what ever details needed about my heads. I have nothing too hide or prove or trying to take work away from any one. Just doing stuff for my self and wanting to learn from some of the good head Porter's that read this board, thats if they are willing too share. What can be done to get the bad port to flow a little more closer to the good port with in 10 to 15 c.f.m. With basic grinding or even adding some Epoxy to the ports to reshape it a way to create a little buffer to help the air move better into the chamber(bore), or create a different short turn in that port. Is that spread (Flow difference) that common on the BB Chevy iron oval port heads. I know the good port has a better natural path for the air to flow into the chamber (Bore) from left to right. The bad port makes a hard right turn into the right side of the chamber (Bore) and then probably dead ends their. I'm all ears on this, so grind (Fire) away.

Thanks for Looking and any info you are willing too share,

Ron Miller 92Camaro:beers:
=
Can't help you with the "bad port" but I do have to say I have never seen a stock oval, even an open chamber one flow those numbers without a ton of work by some one that is really good.
If they in fact flow these numbers the porting would rival that of Larry Meaux or Darin Morgan :thumbsup:

Some of the best oval's I have seen were in the 310-315 area as I recall & they had a ton of money in them according to the owner.
I do not remember how big they were.

just for comparison, here are some numbers of a few heads off a very honest bench
These are off my bench not, advertised.

781's Mild bowl port 2.19/1,88
.05 - 40/33
1 -69 / 56
2 - 158 / 102
3 - 217 / 135
4 - 254 / 161
5 - 263 / 186
6 - 274 / 209
7 - 272 / 219
==============
Perf RPM #60459 290cc Intake port 2.19x1.88 110cc chamber
"Good port"
.050 - 41/ 32
.100 - 73/ 64
.200 - 148/119
.300 - 218/149
.400 - 268/179
.500 - 304/207
.600 - 317/229
.700 - 319/245
"Bad port"
050 - 38/ 31
.100 - 74/ 64
.200 - 146/119
.300 - 218/150
.400 - 260/179
.500 - 291/207
.600 - 307/229
.700 - 302/245
================
RR OVAL 270cc port
.050 - 42/33
100 - 77/65
200 - 152/118
300 - 224/147
400 - 283/178
500 - 318/205
600 - 344/230
700 - 347/248
=============

RR Rect 290cc port CNC chamber intake only 050 - 41
100 - 80
200 - 153
300 - 227
400 - 280
500 - 319
600 - 345
700 - 352
==============
AFR 315 CNC
4.530" ===========4.310" bore
..050 - 40/34 =======43.4
.100 - 78/69 ========78.1
.200 - 164/142.5 =====162.3
.300 - 247/198 ======239.5
.400 - 309/240====== 290
.500 - 350/267 ======334.4
.600 - 375/280 ======358.3
.700 - 383/283 ======374
.800 - 381/286 ======377

All tests @ 28", radius inlet, no pipe, 4.530 bore except the 315intake on the 4.310 bore

===========
And here is some from Bill Jones which as you probably know is not exactly a slouch when it comes to heads but these are at 25" off his bench

"-at -----------------.100", .200", .300", .400", .500", .600"-
int-stock------------ 65----134----180---205---225----255
int-mild ported------65----134----192---230---250----264

exh stock------------54-----97-----120---149---169----186
exh mild ported-----62----109-----144---177---196----204

=======
To get to 28":
Sq root (new press/old press) * flow at old pressure

And I do have a question
How are you getting to 28" on a SF120 with that big of a port?
 

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that's what I was wondering. he must be using the conversion formulas.
 

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Discussion Starter · #7 ·
Mike,
Thanks for the flow info on the different oval port heads. I'm gonna save it for my own reference. Mike and Tom, both you guys are correct. My friend dose indeed use a correction factor for the Superflow 120. I should have stated that in my original post. He will flow a port or heads 2 different times, usually a few hours apart to eliminate any possible errors. As far as his bench being honest, I hope it is. I know when he ordered his bench, he ordered as a upgrade option the more sensitive controls and vacuum motors that are used too flow motor cycle heads and smaller stuff. Their are allot of local guys that will bring heads for him too flow, just to verify their numbers. I can tell you he has flowed many SB2.2 heads from Richard Childress that come with a flow sheet and his bench is about 2 to 3 cfm off their sheet. My friend has nothing too prove or inflate numbers. He has a ton of flow sheets, been porting and flowing heads, building oval track/drag race engines for over 35 years. But this set that I have the flow curve on is my own work with no epoxy/welding in any of the ports. And Yes I do have a ton of work on them, I quit counting after 20 hours and a box of 60 grit rolls. I'm thinking about having them flowed on another bench just to see if the numbers change good or bad. Its not that I don't trust my friends bench, I would like another point of view and more data reference.

Like I said in my first post. I have nothing too hide or prove or trying to take work away from any one. Just doing stuff for my self and wanting to learn from some of the good head Porter's that read this board, thats if they are willing too share.

Thanks Again for the reply,

Ron Miller 92Camaro:beers:
 

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those conversions don't always work properly because the air velocity produced by the larger pressure drop changes the way the port works. Turbulences crop up, stuff like that.

Otherwise, all those guys wouldn't have bought 600's, 120's are cheaper.
 

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those conversions don't always work properly because the air velocity produced by the larger pressure drop changes the way the port works. Turbulences crop up, stuff like that.

Otherwise, all those guys wouldn't have bought 600's, 120's are cheaper.
=
This is correct, especially going from 10 to 28
But as long as you are using the bench as a tool to improve the head & you are comparing apples to apples it is not a big deal except it has been found that as you said at higher test pressures things crop up that you will never see at 10"s & it can really kill flow sometimes.
I typically see heads that were done at 10 inches be down quite a bit at 28.

I believe I read that Larry Meaux for one does most of his velocity probing at something like 38" if he can get there as it gives him a more representative idea of what is actually going on.
You "see" things that are not there at lower depressions.
 

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Discussion Starter · #10 · (Edited)
Tom Mobley Quote: those conversions don't always work properly because the air velocity produced by the larger pressure drop changes the way the port works. Turbulences crop up, stuff like that.

Otherwise, all those guys wouldn't have bought 600's, 120's are cheaper.

Tom, conversion's can work properly if the original data repeats its self. Conversions are used all the time in the Big 3 and even on their flow benches. The SF-120 I'm talking about has the 240 VAC motors in it. It will encounter turbulences just like its big brother SF-600 as this was proved with my heads @ .600 and .700. When comparing Accuracy differences from the SF-120 to the SF-600, its only about .5%, which is about 2 to 4 c.f.m. different in total flow. You will get that 2 to 4 c.f.m difference on any bench located any where in the World, their are so many variables. So are you saying that if a guy has a SF-120, he's waisting his time with that bench because of the .5% Accuracy differences and using a conversion formula.

=
This is correct, especially going from 10 to 28
But as long as you are using the bench as a tool to improve the head & you are comparing apples to apples it is not a big deal except it has been found that as you said at higher test pressures things crop up that you will never see at 10"s & it can really kill flow sometimes.
I typically see heads that were done at 10 inches be down quite a bit at 28.

I believe I read that Larry Meaux for one does most of his velocity probing at something like 38" if he can get there as it gives him a more representative idea of what is actually going on.
You "see" things that are not there at lower depressions.
Mike, I would like to get these heads flowed on a bench capable of a true 28" or up to 38"s just too see and hear what happens in the port and gain more data reference. Their again, the info that I'm seeking is for personal use and get another point of view. I know all the benches out their are for reference proposes only, and I think this SF-120 has its purpose. I know one thing, I'd love to have a New SF-600 or larger, but my pockets are not that deep. In the mean time I'm gonna have to use my friends SF-120 bench.


I was hoping for more replies on this set of heads to compare with. Even if it is 063's, or any other closed chamber heads. I guess I will keep plugging away on this junk set of heads and intake to get a closer balance.

Thanks Again for the replies,

Ron Miller 92Camaro:beers:
 

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Discussion Starter · #12 ·
mr 4 speed,
Thanks for the reply and the chart, I have that. Still looking for more info on how to correct the bad port to the good port. Maybe this is Top Secret Question.

Thanks Again,

Ron Miller 92Camaro:beers:
 

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it's not a Top-Secret Question, it'sa Top-Secret Procedure. In fact, it's so secret nobody has yet discovered it. Some get pretty close though.
 
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