Aftermarket/Replacement Cylinder Head Rule Change

MR DERBY CITY · 12-13-2017, 02:51 PM

Nice, and you guys think that there are NO crate motors in NHRA....

SS734 · 12-13-2017, 03:29 PM

Maybe Mike Crutchfield can give us an update.

Mike Pearson · 12-13-2017, 04:03 PM

Quote:

Originally Posted by MR DERBY CITY

Nice, and you guys think that there are NO crate motors in NHRA....

Its getting real hard to find some of the older factory heads that are 40 years since they have been produced. I welcome the ability to start with a brand new casting. Just keep the original valve size, port volume and chamber volume as original on the NHRA head CC volume list

Chris1529 · 12-13-2017, 04:13 PM

Quote:

Originally Posted by MR DERBY CITY

Nice, and you guys think that there are NO crate motors in NHRA....

Give everyone a stock replacement aluminum intake too and there you go.

Jim Kaekel · 12-13-2017, 04:21 PM

Just say "no".....to aftermarket heads.

Paul Precht · 12-13-2017, 04:28 PM

I could be wrong but I don't think it is practical to use the Edelbrock head on the Max Wedge, the port mismatch would be quite a challenge since you cant enlarge the ports. If they raise the iron head HP to the aluminum head HP the factor would be higher than the original.

SS734 · 12-13-2017, 04:52 PM

Guys you are missing the point here.

Aftermarket heads are already accepted with a HP penalty. There is talk that they will become "replacement" heads and this result will eliminate the different factors of OEM vs. Aftermarket heads for the combos that currently have them.
Trying to find out "if" this does go through, what will happen to the two hp factors that are currently different?

Dwight Southerland · 12-13-2017, 05:13 PM

Conceptually, when you place a different hp factor on an engine because of the use of replacement heads (aftermarket or OEM), you have essentially created a new engine for the books. The problem is the way that classification is calculated since it uses a weight break of one rating and then the weight of the new hp factor. Eliminating the differential of ratings will simplify the calculation for the guys in the field, which is always a good thing since it helps eliminate confusion and mistakes.

CWhitney · 12-13-2017, 08:30 PM

So does this mean that if a combination has been factored 20 HP now its gonna go back to the OG HP rating??

Example 396 Iron head is 375/385
396 Alum head is rated at 405HP

Both heads go back to 375?

SDT1DYI · 12-22-2017, 10:27 AM

Does Edelbrock then make a SBC head with intake runners 161-165 CC's? Edelbrock is the only approved head? All I have seen is 180 CC and up.

Steve Teeter STK 6380.

12-13-2017, 02:51 PM	#1
MR DERBY CITY VIP Member Join Date: Feb 2014 Location: Derby City, USA Posts: 3,639 Likes: 1,083 Liked 7,938 Times in 1,519 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change Nice, and you guys think that there are NO crate motors in NHRA....

12-13-2017, 03:29 PM	#2
SS734 Junior Member Join Date: Apr 2016 Posts: 27 Likes: 5 Liked 4 Times in 3 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change Maybe Mike Crutchfield can give us an update.

12-13-2017, 04:21 PM	#5
Jim Kaekel VIP Member Join Date: Jul 2002 Location: Michigan Posts: 1,227 Likes: 133 Liked 531 Times in 108 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change Just say "no".....to aftermarket heads. __________________ Jim Kaekel 3836 STK

12-13-2017, 04:28 PM	#6
Paul Precht Senior Member Join Date: Dec 2001 Location: Elysburg, Pa Posts: 733 Likes: 359 Liked 327 Times in 121 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change I could be wrong but I don't think it is practical to use the Edelbrock head on the Max Wedge, the port mismatch would be quite a challenge since you cant enlarge the ports. If they raise the iron head HP to the aluminum head HP the factor would be higher than the original.

12-13-2017, 04:52 PM	#7
SS734 Junior Member Join Date: Apr 2016 Posts: 27 Likes: 5 Liked 4 Times in 3 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change Guys you are missing the point here. Aftermarket heads are already accepted with a HP penalty. There is talk that they will become "replacement" heads and this result will eliminate the different factors of OEM vs. Aftermarket heads for the combos that currently have them. Trying to find out "if" this does go through, what will happen to the two hp factors that are currently different?

12-13-2017, 05:13 PM	#8
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,001 Likes: 64 Liked 780 Times in 194 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change Conceptually, when you place a different hp factor on an engine because of the use of replacement heads (aftermarket or OEM), you have essentially created a new engine for the books. The problem is the way that classification is calculated since it uses a weight break of one rating and then the weight of the new hp factor. Eliminating the differential of ratings will simplify the calculation for the guys in the field, which is always a good thing since it helps eliminate confusion and mistakes. __________________

12-13-2017, 08:30 PM	#9
CWhitney Junior Member Join Date: Feb 2008 Location: Sun Valley,Ca Posts: 86 Likes: 2 Liked 12 Times in 6 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change So does this mean that if a combination has been factored 20 HP now its gonna go back to the OG HP rating?? Example 396 Iron head is 375/385 396 Alum head is rated at 405HP Both heads go back to 375?

12-22-2017, 10:27 AM	#10
SDT1DYI Member Join Date: Nov 2016 Location: Indianola Washington Posts: 405 Likes: 0 Liked 455 Times in 147 Posts	Re: Aftermarket/Replacement Cylinder Head Rule Change Does Edelbrock then make a SBC head with intake runners 161-165 CC's? Edelbrock is the only approved head? All I have seen is 180 CC and up. Steve Teeter STK 6380.