Aftermarket/Replacement Cylinder Head Rule Change

[M Brand 505B]

One of the listed heads is close in CC to the stock specs. This rule is good for guys in the cylinder head business. Now we need a head approved for the Pontiac.

[Dan Fahey]

NHRA Approved Aluminum Cylinder Heads

http://www.edelbrock.com/automotive/...approved.shtml

[PJ305]

I have done research on SBC replacement heads and Dart should be the only one approved for Stock. If NHRA is looking here you go.
"DART" WISSOTA #30424361 or #10024361 bare casting plain and simple.I don't believe replacement heads are needed and why would you allow so many with totally out of whack specs. This head is the only one close to Stock, it is cast iron and is very close to your aftermarket specs.If you ever do teardowns you can police one head easier than 8 different ones! Yeah and by the way why isn't it on the list?

[Paul Merolla]

What a can of worms they've opened now....
The Edelbrocks, aside from the fact that they're aluminum, are made for 2.02/1.60 valves and 1.46" springs. So many more grey areas have just been created, and for what?? "But I can't find any old castings!" BS!! I'll buy that line for other brands, but for small-block Chevys?? Get off the couch.
Well, now there's another 5G just to keep up. Thanks.

[Alan Roehrich]

Dart or Engine Quest cast iron replacement style heads would have been the correct choice.

However, I'm guessing that neither of them went to the trouble or expense to submit anything.

Anyone who has been through the NHRA approval wringer for anything will understand, especially if they've had parts rejected for subjective illogical reasons.

Aluminum heads for Super Stock make sense, considering the alterations allowed, and the easier repair of aluminum. For Stock, not so much, they just allow cheaper and easier cheating.

[Bob Mulry]

I think that we are missing the point on these replacement heads...

Runner volume is just one way to compare castings...

With the new replacement castings I would like to know what the flow numbers are from each head..

Just because the volumes are the same it has nothing to do with air flow or the horsepower that they are capable of making..

It looks like another can of worms just got opened for Stock...

Just sayin'

[SS734]

If the HP number is low enough, it doesn't matter what head is on what engine.....Take a look at Nitro Joes stats and see who's at the top of the heap in all classes!!!


Still no answer as to how they are combining and reducing to combos.


Anyone care to put their 2 cents in???

[Bobby Lundholm]

Since the new heads come with 2.02 valves to you have to make them comply with the 1.94 valves or run them as they came?

[Crew Chief]

I can remember a time when a friend submitted a replacement head to NHRA. He was told to bring the new head to a national event along with an OEM head for comparison . The head was looked at by techmen who knew what they were doing. They rejected the head because the intake runner and combustion chamber had been changed in the new casting.

One wonders if the same procedure is used today when a new head gets accepted. By the way, who is accepting all this stuff anyway?

[M Brand 505B]

Originally Posted by Bobby Lundholm

Since the new heads come with 2.02 valves to you have to make them comply with the 1.94 valves or run them as they came?

The Aftermarket head has to retain the same specs as the head it's replacing.