Bench flowing heads ??
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Bench flowing heads ?? i have noticed that some head porters use a 4.0 bore when showing there flow #'s and a few use 3.9 bore which i would assume should be the one to judge by. Now here's my ? what type of gains are added when using a 4.0 bore to the head flow?
Bore Fixtures...
Originally Posted by destroyerSS
Anyone???
The net change between a 3.900" and the 4" bore certainly wouldn't be as dramatic as with a 4.125, but once again, some heads will be hurt a little, some heads will be hurt alot. The only real way to really learn and quantify is to have them flowed on both bore fixtures.
Hope this helps you out,
Tony Mamo
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From: Orange county n.y.
Thanks Tony for the info 
I guess the point i'm trying to get to is why would'nt all of the head porters on this site go off of a 3.900 bore since this is what the majority of us run and then offer flow #'s for larger bores as well but for the norm they should use our standard bore size. This way people will get a better idea of what company's heads flow vs anyone else heads instead of thinking company's Y's head flows 310 @600 w/ 3.900 bore vs company X whose heads flow 320 @600 w/ 4.125 bore. I think using larger bore size is just kinda 
!! Again thanks tony and sorry for my rambling on. Thanks Shawn
I guess the point i'm trying to get to is why would'nt all of the head porters on this site go off of a 3.900 bore since this is what the majority of us run and then offer flow #'s for larger bores as well but for the norm they should use our standard bore size. This way people will get a better idea of what company's heads flow vs anyone else heads instead of thinking company's Y's head flows 310 @600 w/ 3.900 bore vs company X whose heads flow 320 @600 w/ 4.125 bore. I think using larger bore size is just kinda !! Again thanks tony and sorry for my rambling on. Thanks Shawn 
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From: Working in the shop 24/7
Originally Posted by destroyerSS
Thanks Tony for the info I guess the point i'm trying to get to is why would'nt all of the head porters on this site go off of a 3.900 bore since this is what the majority of us run and then offer flow #'s for larger bores as well but for the norm they should use our standard bore size. This way people will get a better idea of what company's heads flow vs anyone else heads instead of thinking company's Y's head flows 310 @600 w/ 3.900 bore vs company X whose heads flow 320 @600 w/ 4.125 bore. I think using larger bore size is just kinda !! Again thanks tony and sorry for my rambling on. Thanks Shawn
I guess the point i'm trying to get to is why would'nt all of the head porters on this site go off of a 3.900 bore since this is what the majority of us run and then offer flow #'s for larger bores as well but for the norm they should use our standard bore size. This way people will get a better idea of what company's heads flow vs anyone else heads instead of thinking company's Y's head flows 310 @600 w/ 3.900 bore vs company X whose heads flow 320 @600 w/ 4.125 bore. I think using larger bore size is just kinda !! Again thanks tony and sorry for my rambling on. Thanks ShawnFlow numbers are all relative....
If one shop tests on a 3.900 and so does another shop, and one gets more "numbers".... is this saying the "bigger" numbers are better? Hell NO!!!
Besides the "obvious" differences in methods "and" equipment, there are too many variables to say one cylinder head is "better" than the other...
Port volumes...
300 CFM with 205 vs 235 cc port volume... Which would you want?
Velocity....
Get some velocity probe data too!
Quality of the airflow...
Can you say turbulence???
Application....
Supercharged, turbo or naturally aspirated???
Cam profile...
A bad cam design will kill a good head package and vice versa....
There are plenty of lower "number" CFM cylinder heads that OUTPERFORM the big number pieces on the racetrack... I see it all the time in the Ford heads up racing series...
Ed
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EDC, I should of added port volume to my orignal ? Good point!! As far as the 3.900 bore i think they should use this as a standard. Then people can gather results from flow #'s & port volume size's from the head porter to use as a starting point then check for track result's and make there choice. If company's didn't think flow #'s were not inportant why would some chose to flow check with a larger bore? maybe for higher #'s Not trying to argue! but i just like when you can choose a product with equal testing 
Not trying to argue! but i just like when you can choose a product with equal testing 
