Cylinder head question,again.

Terry Cain · 09-07-2009, 06:54 AM

Also, it's possible to cut intake or exhaust side of head or intake to make it a little smaller. NOT much room to work with here though.

Jody Lang · 09-07-2009, 11:06 AM

I should start a new thread for this, but I'll start here. There's a problem in the specs for the Stockers. I personally know of 4 people that have checked their runners and all 4 have been big on the exhaust. These are various Chev motors. In 3 of these it's only been 1 of the heads that's been big.

These are not acid heads either. The specs were for the Super Stock heads. Those that could braze/epoxy in the ports to get the desired CC's.

The new rule is affecting innocent racers that just assume their ports are ok because they're stock.

Jeff Lee · 09-07-2009, 02:46 PM

You can reduce the runner volumes by cutting the intake or exhaust surfaces as mentioned. Rule says you can not go past the valve cover bolt hoe.
You can also reduce those volumes by sinking the valve(s) deeper in the pocket. With some valve jobs you can gain flow by doing this correctly. Key word is correctly.
If it was a particularly rare head I would look at all avenues. If it's your dime-a-dozen head I'd scrape it.
And no, there is no tolerance on the plus side.

09-07-2009, 04:45 PM

I agree with what Jeff Lee is saying. I have fixed this problem a few times before. You can sink the valve/seat, which in most cases can reduce 3cc's or more depending on the valve diameter. And in most cases will increase the flow and air speed thru the port. Call or email me if you need help with this.
Best Regards,
Chris Hardy
231-773-7252
chrishardy@racingenginetechnologies.com

09-07-2009, 06:54 AM	#1
Terry Cain Senior Member Join Date: Feb 2008 Location: Georgetown, Indiana (close to Louisville, KY) Posts: 778 Likes: 530 Liked 231 Times in 107 Posts	Re: Cylinder head question,again. Also, it's possible to cut intake or exhaust side of head or intake to make it a little smaller. NOT much room to work with here though. __________________ Terry Cain ???? STK tcain19689585@gmail.com

09-07-2009, 11:06 AM	#2
Jody Lang Member Join Date: Mar 2002 Posts: 306 Likes: 28 Liked 89 Times in 28 Posts	Re: Cylinder head question,again. I should start a new thread for this, but I'll start here. There's a problem in the specs for the Stockers. I personally know of 4 people that have checked their runners and all 4 have been big on the exhaust. These are various Chev motors. In 3 of these it's only been 1 of the heads that's been big. These are not acid heads either. The specs were for the Super Stock heads. Those that could braze/epoxy in the ports to get the desired CC's. The new rule is affecting innocent racers that just assume their ports are ok because they're stock.

09-07-2009, 02:46 PM	#3
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Cylinder head question,again. You can reduce the runner volumes by cutting the intake or exhaust surfaces as mentioned. Rule says you can not go past the valve cover bolt hoe. You can also reduce those volumes by sinking the valve(s) deeper in the pocket. With some valve jobs you can gain flow by doing this correctly. Key word is correctly. If it was a particularly rare head I would look at all avenues. If it's your dime-a-dozen head I'd scrape it. And no, there is no tolerance on the plus side. __________________ Jeff Lee 7494 D/S '70 AMX

09-07-2009, 04:45 PM	#4
Chris Hardy Guest Posts: n/a	Re: Cylinder head question,again. I agree with what Jeff Lee is saying. I have fixed this problem a few times before. You can sink the valve/seat, which in most cases can reduce 3cc's or more depending on the valve diameter. And in most cases will increase the flow and air speed thru the port. Call or email me if you need help with this. Best Regards, Chris Hardy 231-773-7252 chrishardy@racingenginetechnologies.com