Cylinder Head Runner Volumes

[zracer305]

Originally Posted by terry1

I have a question.If a set of heads are larger than the published runner volumes,for what ever reason,core shift(LOL)etc.will the powers that be(IHRA,NHRA)allow the runner(s) to be filled to get to the correct volume?
If so,will that not open the door(if not already open)to acid/undercover port your heads to get the optimum flow rate then fill down/up to correct volume,sort of like a Superstock job with out the pollishing.

From the Lucas page:
Regardless of the poured volume measurement, any modifications to intake and exhaust runners are prohibited. Any evidence of modifications from the original castings will be grounds for disqualification. Final decision at the discretion of the Technical Services Department.

In my conversation with Bruce I asked the very same question. There can be no modifications in the runners at all. If it looks like modifications have been done, even if you are within the volume tolerances it will be considered grounds for disqualifications. Acid porting and/or undercover porting is not and has never been permitted in Stock.

[Billy Nees]

Originally Posted by zracer305

From the Lucas page:
Regardless of the poured volume measurement, any modifications to intake and exhaust runners are prohibited. Any evidence of modifications from the original castings will be grounds for disqualification. Final decision at the discretion of the Technical Services Department.

In my conversation with Bruce I asked the very same question. There can be no modifications in the runners at all. If it looks like modifications have been done, even if you are within the volume tolerances it will be considered grounds for disqualifications. Acid porting and/or undercover porting is not and has never been permitted in Stock.

Riiiiggggghhhhhttttttt.

[SS Engine Guy]

Originally Posted by zracer305

Acid porting and/or undercover porting is not and has never been permitted in Stock.

I fully understand the intent of your statement as it has been stated in the rule book. However, it may have not been permitted however, it sure has been ACCEPTED on numerous occasions for whatever reasons.

Again this begs the question: What if my perfectly stock unmodified heads are 20 cc's smaller than the allowed SS spec? Do you modify them, look for a set of modified heads that have passed tech, or just take your beating from illegal entries?

[X-TECH MAN]

Im with Billy Nees on this one. What a joke unless they do a 180 degree turn around and we all know that will happen.....lol.

[zracer305]

Originally Posted by SS Engine Guy

I fully understand the intent of your statement as it has been stated in the rule book. However, it may have not been permitted however, it sure has been ACCEPTED on numerous occasions for whatever reasons.

Again this begs the question: What if my perfectly stock unmodified heads are 20 cc's smaller than the allowed SS spec? Do you modify them, look for a set of modified heads that have passed tech, or just take your beating from illegal entries?

Let me break this into two parts because what you are talking about is two different topics.

Part I
You would be best to direct this to the NHRA tech directors. I am not here to defend them or what has gone on in the past. All I can say and am trying to do is forward what information I know from talking directly to NHRA myself. If you have an issue with them I would like to suggest you do the same.


Part II
I find it hard to believe that factory heads could be 20cc's smaller or 20cc's larger than what is posted for SS. That’s a 40 cc margin of error you talking about. But, if your perfectly stock unmodified heads are 20 cc's smaller than the allowed SS specs; you have a couple of options. You can continue to run them and hope you never have to run heads up. Or, you can do what I did. Go to the junk yards and buy several sets of heads that look good to you. Buy the correct equipment to cc the runners yourself. Then take only those castings and have them cleaned, pressure tested and mag’ed. Once you are narrowed down to two sets, leave one in your garage and take the best set to your machine shop for a competition valve job as defined in the rule book.

[SS Engine Guy]

edited ..........