Re: Cylinder Head Runner Volumes
 

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.

Re: Cylinder Head Runner Volumes
 

Now take it easy on me here I'm a newbie to this. Am I understanding this right... the runner volumes on the stocker heads go by the ss cc list?

Re: Cylinder Head Runner Volumes
 

Yes, you are correct. However, in 2010 there will be two separate lists, one for Stock and one for Super Stock.

http://www.nhra.com/tech_specs/runners/index.html

Re: Cylinder Head Runner Volumes
 

I don't run Stock any longer for my own reasons and I won't bore you all with why that is so. I have poured a number of intake runners in my engine shop days. Mostly big and small block Chevys that were untouched. I also poured the heads that were on my last stocker...a late model LT-1 with aluminum heads. Lets just say that my experience is that all the heads I poured were not near the posted NHRA numbers, How did they get those numbers in the first place one would have to ask. Especially if the rules say NO port modifications allowed including acid porting or what I might call "selective rusting techniques". Aluminum does not rust so I also have to ask how a head spec can be close to 10 CC's larger than an unmolested head? The heads used to establish the accepted numbers were modified in my opinion. That is old news......

Re: Cylinder Head Runner Volumes
 

Rich, I did a set of quicky LT1 SS heads myself last spring when I got a wild hair to go SS racing again (In like three weeks, I'm not real bright.). I had two sets of salvage yard castings, all poured very close to each other. NHRA said 175 cc intakes, all of mine were very close to 170. Exhausts were about 5 small also. I can't imagine how a set could be 165 cc. Even a valve job would not make them that much smaller.
Had the intake gasket surface been cut? Were your end chambers smaller than the centers? All four of mine were, like over 1/2 cc.

Sending one set to Dave Layer was a very good move. 40 ftlbs better than mine.

Re: Cylinder Head Runner Volumes
 

edited ..........

Re: Cylinder Head Runner Volumes
 

I also poured the heads that were on my last stocker...a late model LT-1 with aluminum heads. Lets just say that my experience is that all the heads I poured were not near the posted NHRA numbers, How did they get those numbers in the first place one would have to ask. Especially if the rules say NO port modifications allowed including acid porting or what I might call "selective rusting techniques". Aluminum does not rust so I also have to ask how a head spec can be close to 10 CC's larger than an unmolested head? QUOTE FROM RICH

Exactley... where did they get these #'s... for super stock, no problem make em bigger... if they are bigger than SS make em smaller by welding or epoxy... for stock, if there bigger than what you need and you cant find any cores that small cause there aren't any... DON'T RACE THAT COMBO..

Re: Cylinder Head Runner Volumes
 

Bub, you're my hero! Kiss, kiss

Re: Cylinder Head Runner Volumes
 

Ed...I am going by memory on the LT-1 heads and they came up about 7 or 8 cc's under the max on the intake side. Those heads came with the car I bought as a roller. They were prepped by Heads-up and I just puffed them up very lighty and rechecked all the chambers for CC's. Straight stemmed valves, not undercut and they came with the heads. Being a "newby" at the time at building this Stocker engine...I relied on some parts and help from Woodro and I was able to run some decent numbers. I needed a man like you to help me tune the ECU as I see you are very skilled at that.........Hi Billy......

Re: Cylinder Head Runner Volumes
 

Or give NHRA an unmolested head, let them pour it and fix the number. Or have LT-1 heads become so rare already that NHRA has to accept the big number or allow a "replacement" aftermarket head. Or pick another excuse, lets see, the collectors have bought up all of the cores, racers have modified all of the cores already, NHRA is just picking on all of MY cores, my dog pissed on my cores and that's why they're so big, they got accidently buried in my back yard and salted 10 years ago, I'm way too busy making tons of money so I have to rely on other people and they screwed up or the best one, my lawyer says that it's OK because none of the NHRA tech people can be considered "experts" in a court of law.
BTW, while reading this just remember that it was written by a cynical, old crazy man that is snowed in on a hill in central Pa..