[Stan Weiss]

Originally Posted by PontiacJim1959

I can't comment on it as I wasn't there. I had a younger guy I work with whose dad has an engine machine shop and builds Nascar, dirt track, and other winning competition engines. He has all the latest equipment and I think the flow bench was a Superflow? He used a BB Chevy 4.25" flow cylinder as my 455 is .060" over. There is a column listed "Range" and the .100" lift number is shown as "Range 3" and 63% while all other numbers are listed as "Range 4." Have no idea what that means and that my explain the lift number?

His dad used to be the head porter for a nascar team. He was pretty impressed with the heads and said they should be capable of 500HP. I am not shooting for 500HP as I don't have the compression or cam. I think 400HP-425HP with good TQ numbers is more realistic and good enough for the street.

I do not know what flow bench he was using. This table is for a Super Flow 1020. Range 3 is 100 CFM so 63% would be 63 CFM.

Stan

PS - OK found my Super Flow 600 manual. It lists range 3 as 150 CFM so 63% would be 94.5 CFM.

[PontiacJim1959]

Originally Posted by Stan Weiss

I do not know what flow bench he was using. This table is for a Super Flow 1020. Range 3 is 100 CFM so 63% would be 63 CFM.

Stan

OK, thanks Stan, first time I have ever flowed a head.

So how does that relate to my flow numbers? Are you saying that the flow at .100" lift is 63 CFM, and not the 94.5 CFM shown on my chart?

Is it a conversion, ie like 20 Hg versus 28 Hg?

[Stan Weiss]

Originally Posted by PontiacJim1959

OK, thanks Stan, first time I have ever flowed a head.

So how does that relate to my flow numbers? Are you saying that the flow at .100" lift is 63 CFM, and not the 94.5 CFM shown on my chart?

Is it a conversion, ie like 20 Hg versus 28 Hg?

Jim,
I have no idea what model Super Flow flow bench he used, if he used a Super Flow flow bench. Check my post which I edited after you quoted it.

Stan

[steve25]

Those benches are calibrated to 25" so I can only assume by that big number at.100" that he was testing at 28" which is fine, but that's one of the most important things to have noted on any flow sheet you handed!

To convert flow @ 25" to 28" you X by 1.06, this leads you to see that he could not have possiblely run the flow test at 25"because that rounded off 94 cfm number would then be 99 cfm.

[Stan Weiss]

A few head from my list.

Pontiac 6X-4 Ported Iron
2.11
0.10000 - 89
0.20000 - 143
0.30000 - 165
0.40000 - 222
0.50000 - 238
0.60000 - 244
1.66
0.10000 - 48
0.20000 - 90
0.30000 - 122
0.40000 - 146
0.50000 - 156
0.60000 - 163

Pontiac 6X HPP Iron
2.11
0.10000 - 88
0.20000 - 153
0.30000 - 206
0.40000 - 221
0.50000 - 232
1.77
0.10000 - 85
0.20000 - 122
0.30000 - 164
0.40000 - 185
0.50000 - 196

Pontiac 455 HO '71 197 Flowtech - Steven Magnotti 3 Angle VJ
Cut SF110 Iron
2.11
0.10000 - 88
0.20000 - 160
0.30000 - 199
0.40000 - 219
0.50000 - 234
0.55000 - 240
0.60000 - 241
0.65000 - 243

Pontiac 62 Ported Paul Carter Iron
2.11
0.10000 - 86
0.20000 - 148
0.30000 - 188
0.40000 - 240
0.50000 - 255

Stan

[steve25]

Stan those HPP numbers for the 6X head exh itted with a 1.77” valve are really quite high, like something was not set right or something, or the seat or stem was leaking and or had no valve seal on it.

I have never seen 85 cfm @ .100” out of other brand heads even when they used a 1.81” valve, and maybe also even with a 1.88” valve , but I would have to dig out my BBC notes to confirm that,.

[Half-Inch Stud]

Pushrod bulge is the Flow-Choke in both CSA minimum and turbulence generation. I think.

[steve25]

Not by a long stretch!
In terms of a 6X head the port circumference of the 1,60” throat of the valve bowl is 5.02”, the port circumference at the push rod bulge is 5.337” , so the throat is the minimum port area with the circumference at the crown of the short turn a close second!

[PontiacJim1959]

Originally Posted by Stan Weiss

Jim,
I have no idea what model Super Flow flow bench he used, if he used a Super Flow flow bench. Check my post which I edited after you quoted it.

Stan

Stan,
.
Thanks for your updated reply. I plan on going to the shop in the next couple weeks to check things out and see what all is done and the equipment. I will do some inquiring on the head flow numbers and hopefully learn a little.

I only did the flow testing just to satisfy my own curiosity. I usually do basic port work on any performance engine I have assembled and can't say I have assembled a bunch of them, but have done this on Chevy small blocks, my brothers Mopar small block, and my Pontiacs. First time I ever went to the extent I did on these heads. Never had any issues, and the engines always pulled hard, but these were street cars as opposed to a race/track car which would be more critical in attempting to get all the HP you can.

I plan on a small shot of nitrous, just because, so that'll give me a small boost in power added to a hopeful 400-425HP build.

Once I get the scoop on flowing heads from the shop that did them, I will post what I am told on my heads.

[Stan Weiss]

Originally Posted by steve25

Stan those HPP numbers for the 6X head fitted with a 1.77” valve are really quite high, like something was not set right or something, or the seat or stem was leaking and or had no valve seal on it.

I have never seen 85 cfm @ .100” out of other brand heads even when they used a 1.81” valve, and maybe also even with a 1.88” valve , but I would have to dig out my BBC notes to confirm that,
When porting the

Steve,
The HPP numbers came from High Performance Pontiac Magazine. Maybe someone has some old issues and can see if they have the magazine where those numbers came from.

Stan

[PontiacJim1959]

Originally Posted by steve25

Those benches are calibrated to 25" so I can only assume by that big number at.100" that he was testing at 28" which is fine, but that's one of the most important things to have noted on any flow sheet you handed!

To convert flow @ 25" to 28" you X by 1.06, this leads you to see that he could not have possibly run the flow test at 25"because that rounded off 94 cfm number would then be 99 cfm.

I will find out when I visit the shop. From my reading/understanding, 28Hg is a basic standard most use like the .050" number cam manufacturers use. I know 20Hg & 25Hg are used. So another important piece of info needed in comparing/converting flow numbers.

I think it would also be important to know what the calibration is with regards to the CFM the flow bench uses. I have seen the articles, "Build Your Own Flow Bench" using vacuum cleaners, but I would think you still need to know what kind of CFM's even those units would pull?

The same shop has an engine dyno and the guy I work with said it is set to be 20HP low - which they are aware of, and how they run their engines. He was not sure why, only that his grandfather who started the shop/business set it up that way. My thinking is that most dyno's use an electric motor to run the water pump and if you had the basic fan/belts (maybe an Alt.) that these would consume that 20 HP needed to operate them. Another question I'll ask.

[steve25]

I don’t mean to say that a bench calibrated for 25 will not be accurate at 28”, it’s just that you have to know what test pressure the test was done at to compare Apples to Apples so to speak.

[steve25]

Stan, over the weekend I will see if I have that issue of HPP for you.

[Tandyman]

I believe those flow numbers came from this article .
https://www.hotrod.com/articles/0501...-dyno-results/

Glenn

[ponjohn]

I have quite a few flow sheets saved from over the years if anyone wants to see some of the iron ones.

[Half-Inch Stud]

Didnt read this thread. Pushrod bulge zone is the least CSA, and provides a shock surface. Was the pushrod buldge taken down?

[RH68]

Pushrod bulge was not modified. What is CSA?

Originally Posted by Half-Inch Stud

Didnt read this thread. Pushrod bulge zone is the least CSA, and provides a shock surface. Was the pushrod buldge taken down?

[P@blo]

Originally Posted by RH68

Pushrod bulge was not modified. What is CSA?

Cross sectional area

[steve25]

Hi Stan! I found that HPP issue you got those 6X flow numbers from.

It was in the Jan 2005 issue in which bowl ported and cleaned up 6X heads fitted with a 1.77” exh valve and a 3 angle valve job ( from what they state ) where dyno tested by Cliff against KRE’s new D port heads.

The exh numbers you took from the article you got right, but I think the testing of the exh side of the 6X head at .100”was off by being really tested at .102, or .103”, as that’s all it would take to to get that what I call too high 85 cfm numbers.

The reason I say this is not only because I have never seen a 85 cfm number like that out of any work I have done, but also due to the posted intake flow number for that 6X head at .100” of 88 cfm, only 3 cfm higher then that 85 cfm exh number.

When you consider that at .100” a 2.11” valve has a curtain area of .662” and a 1.77” valve has only a curtain area of .552”, then at least to me that adds to my questioning of those numbers!

Here are some flow numbers of 2 KRE high ported high port heads fitted with there stock 1.71” valve.

As you can see none of them do better then 66 cfm@ .100”.

The last flow sheet I will post is the stock exh flow from a Brodix big Brodie head with its stock 1.88” exh valve which makes for a curtain area at .100” of .590”, or 8 percent greater curtain area then .555”, yet there is only 61 cfm taking place.

So to me, like I have stated either the valve opener for the 6X exh test was open more then .100”, or one of the 2 guys at HPP who wrote up that article transposed a number 8 whete there should have been a number 6!

This is my best guess on this, but I am not saying that 85 cfm is not possible, but it certainly isn’t normal to me!

[P@blo]

Jim Hand's book lists stock 6X intake flow at 80 cfm @.100" and 81 with a Ported runner on a 15" bench converted to 28" of water. Looking at the exhaust numbers they are 52 cfm stock and 65 with a Ported runner and the larger 1.77" valve used.