[mgarblik]

In a rules restricted class like NHRA Stock, you just have to work within them. The heads are so limited in flow, all you can do is open the valve as quickly as possible and keep it open as long as possible. Any duration allowed. You end up with rectangular cam lobes and hope for the best. Valve springs become super important. Lifters and cams don't last long.

[ponyakr]

Originally Posted by mgarblik

In a rules restricted class like NHRA Stock, you just have to work within them. The heads are so limited in flow, all you can do is open the valve as quickly as possible and keep it open as long as possible. Any duration allowed. You end up with rectangular cam lobes and hope for the best. Valve springs become super important. Lifters and cams don't last long.

Yeah, some of that's true.

BUT, those things alone won't produce the quick times SOME cars are posting.

Therefore, SOME Stocker heads fudge on the rules, therefore producing much more flow than the stock, as produced, ports will flow.

What I'm saying is NOT a secret. It's a well known fact that Stocker guys have been modifying head ports, for a long time, to increase flow.

My guess is that some of these guys got caught, back in the old days. But, I'm thinkin that nowadays, you'd have to have a really big, obviously enlarged or otherwise modified port, in order to provoke a DQ at an NHRA race.

I suppose they COULD check the ports really close & DQ a Stocker. But, somehow, at this point, I don't think they will. Could be wrong tho.

To me, it would be REAL interesting to get a good close up look at a stock, as cast, 670 head, right beside a head off Randi Lyn & Bryan Phillips' '67 Stockers. Might be rather "eye opening", especially to you guys who have done lots of Pontiac head porting, & are very familiar with 670 heads.

On the other hand, it might actually surprise me, if I could see no difference in the ports, at all. I'll never get that chance, & probably nobody else will, except those involved with the cars and/or head prep.

Lot's of the current Stock racers spend many thousands of dollars for heads that will flow enuff to produce the big numbers needed for class wins & nat records. As long as there are those willing to spend the big bucks, there will probably be guys who will build those heads.

BUT, thankfully, due to the breakout rules used for the rounds which are not same-class heads-up runs, maybe Stock Eliminator will survive for a while longer. Many of the Stock/SS guys HATE it when anyone likens their form of racin to bracket racing. Some will get downright nasty with anyone who even suggests a similarity. BUT, in spite of that, without the breakout rules, Stock/SS would probably not exist today. Only the super rich could win.

All the slower, really soft combinations would eventually disappear, & Stock/SS would become more of a "pro" class. NHRA could make most any combo completely non-competitive, with one hp factor hit.

But, as long as the breakout rule is in effect, any car that will pass tech & teardown, & can run it's index or quicker, it can win a race.