General Cylinder Head Flow Numbers discussion

[SSDiv6]

Originally Posted by HawkBrosMav

I guess I don't how that wording changes anything with the way the rules were written before... It already spells out what can be done and what can't be done as far as "alterations" so that would fall into "unless otherwise specified" meaning that all the heads that passes last year will pass this year just the same..

"unless otherwise specified" refers to the NHRA approved aftermarket cylinder heads.

[Stan Weiss]

Originally Posted by SSDiv6

"unless otherwise specified" refers to the NHRA approved aftermarket cylinder heads.

Since in stock eliminator you can not fill the port. How many of the after market replacement heads in the NHRA Acceptred Products list have a port volume that is legal?

Stan

[Dissident]

There are some heads out there that have been welded prior to reshaping. Cylinder port volume varies a great deal on castings, but can be closely controlled after being "tuned up" as it were.
Although such things might be beyond the regular guy's interest or budget, others have done so (paid to have it done).

Regards,
HB2
Dissident

[HawkBrosMav]

Originally Posted by SSDiv6

"unless otherwise specified" refers to the NHRA approved aftermarket cylinder heads.

A) I see how you are reading that and I don't disagree with your statement, BUT I still don't see how this addition to the wording of the rules changes how they can be applied. The sentence already had "etc." in the verbiage which opened it to any interpretation NHRA could come up with...

B) if you read that and ignore the cylinder head addition it clearly deems literally every single Stock Eliminator car illegal... name me one single car that is running Stock factory OEM unaltered pushrods... in addition to that find me the rule that says we can even run larger diameter or thicker wall pushrods. At least there is a whole section on what can and cannot be done to cylinder heads.

The Blueprinting rule is written to basically say you can only use aftermarket parts when they are listed on the "NHRA Accepted products list" otherwise you have to use OEM unaltered pieces. We all know this isn't the case based on the multitude of rules that follow this statement so them adding cylinder heads to the verbiage doesn't make any sense and unless they can explain to me what it actually changes in application means absolutely nothing..

now that we had this little tangent about a rule "change"... i'd like to try and steer this post back on topic... Other than flow holding past max vlave lift and a quiet port are there any specifics you're looking for from head A to head B to determine one is a .500 under head and one is a record setter? I want to restate.. I'm not looking for the HOW you did it or what you did to to find the best cores to start with...I simply want to have 3 sets of heads.. all starting from an equal "these three heads are the BEST i can find"

-Head A stock completly untouched
-Head B has flow characteristics that make me feel like it will be okay (.5 under)
-Head C has flow characteristics the make it a record setter

Knowing all 3 heads will pass tech what does Head C's flow numbers, port velocity, or anything else you can use to analyze a head on paper look like that makes it the one you chose over Head B.. Again physical things done to the head I'm not asking about. If I handed you the flow printout of 2 separate heads ported by 2 separate people and told you to pick the one you thought would be fastest cause you were headed to INDY tomorrow what is the most important thing on that print out that would sway you to pick one over the other. Or how do you rank the things you look at when making that choice.. as I'm sure it's not just one thing going into that decision.

This might be too much to ask as I'm sure there are many people out there that probably make a bunch of money knowing why stuff goes fast and what their intended goal is when they flow something to know they've got a winner, but if someone is willing to talk about it that's why im asking.. Thanks

Brad

[Adger Smith]

Sure looks like my old Boss has been at work on the rules.
Giving a little and taking a little with things camouflaged. LOL WR

Brad,
You would need to send me a little more info than 2 flow sheets.