1967 belvedere claimed as a gtx.

melvin wellman · 10-02-2022, 03:27 PM

Can you claim a 1967 belvedere as a gtx to use the 440? Also, this motor uses the 915 ( closed chamber) head. But the engine specs guide offer the 906 ( open chamber) head to be used also. Would you shave the 906 head to make it a closed chamber head? Or is there a different way to go about this? Thanks in advance for any explanation, I really don't know who else to ask about this stuff.

Paul Precht · 10-02-2022, 03:43 PM

The 906 can be milled to 915 spec and both heads have basically the same ports. You may have to mill the 906 more but not much. The 915 head requires a .0062 cut per CC and the 906 is .0042 per CC. There are currently some 67 Belvedere's running as GTXs in Stock.

GTX JOHN · 10-02-2022, 05:06 PM

Is there any benefit to running the 906 head
over the 915?

Frank Castros · 10-02-2022, 05:29 PM

At one time way back when the 906 specs approved by NHRA Tech were considered bogus. Kent Ritter was rumored to be responsible for that. I'm sure nobody will refute this.

1347 · 10-02-2022, 08:33 PM

not sure how much you have to take off a 906 head to turn it into a closed chamber head, but won't that effect piston to valve?

GTX JOHN · 10-03-2022, 02:17 AM

Quote:

Originally Posted by 1347

not sure how much you have to take off a 906 head to turn it into a closed chamber head, but won't that effect piston to valve?

Absolute it will!

I sold two nice sets 915 that were nice Pairs this week = $400 pr.

Steve Stasko · 10-03-2022, 07:43 AM

Quote:

Originally Posted by 1347

not sure how much you have to take off a 906 head to turn it into a closed chamber head, but won't that effect piston to valve?

Speaking from experience... If you take the 906 down to closed chambers, it's not a matter of if they will crack between the cylinders, but when. I suppose in a Stocker though, cutting the surface down to 74 cc, it's still going to leave a little of the chamber in the head.

Paul is pretty close on his numbers. The last 906 I measured was 85-86cc, and I know it had a light cut. If I was going to cut an open chamber head down though, I'd use a 452.

melvin wellman · 10-02-2022, 08:35 PM

I have some open chamber heads, but no 915's. thanks for the help , its much appreciated.

melvin wellman · 10-02-2022, 08:39 PM

Good point about valve clearance, I did not consider that.

10-02-2022, 03:27 PM	#1
melvin wellman Junior Member Join Date: Jan 2015 Location: boulder, mt Posts: 14 Likes: 0 Liked 2 Times in 2 Posts	1967 belvedere claimed as a gtx. Can you claim a 1967 belvedere as a gtx to use the 440? Also, this motor uses the 915 ( closed chamber) head. But the engine specs guide offer the 906 ( open chamber) head to be used also. Would you shave the 906 head to make it a closed chamber head? Or is there a different way to go about this? Thanks in advance for any explanation, I really don't know who else to ask about this stuff.

10-02-2022, 03:43 PM	#2
Paul Precht Senior Member Join Date: Dec 2001 Location: Elysburg, Pa Posts: 732 Likes: 357 Liked 326 Times in 120 Posts	Re: 1967 belvedere claimed as a gtx. The 906 can be milled to 915 spec and both heads have basically the same ports. You may have to mill the 906 more but not much. The 915 head requires a .0062 cut per CC and the 906 is .0042 per CC. There are currently some 67 Belvedere's running as GTXs in Stock.

10-02-2022, 05:06 PM	#3
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,733 Likes: 2,799 Liked 2,485 Times in 697 Posts	Re: 1967 belvedere claimed as a gtx. Is there any benefit to running the 906 head over the 915? __________________ John Irving 741 Stock 741 Super Stock

10-02-2022, 05:29 PM	#4
Frank Castros VIP Member Join Date: Nov 2001 Location: The Lowcountry. Posts: 2,973 Likes: 2,586 Liked 2,723 Times in 960 Posts	Re: 1967 belvedere claimed as a gtx. At one time way back when the 906 specs approved by NHRA Tech were considered bogus. Kent Ritter was rumored to be responsible for that. I'm sure nobody will refute this.

10-02-2022, 08:33 PM	#5
1347 Senior Member Join Date: Aug 2007 Location: Monroe Twp NJ Posts: 505 Likes: 1,034 Liked 996 Times in 275 Posts	Re: 1967 belvedere claimed as a gtx. not sure how much you have to take off a 906 head to turn it into a closed chamber head, but won't that effect piston to valve? __________________ Duane Hoven 1342 SS/GT

10-02-2022, 08:35 PM	#8
melvin wellman Junior Member Join Date: Jan 2015 Location: boulder, mt Posts: 14 Likes: 0 Liked 2 Times in 2 Posts	Re: 1967 belvedere claimed as a gtx. I have some open chamber heads, but no 915's. thanks for the help , its much appreciated.

10-02-2022, 08:39 PM	#9
melvin wellman Junior Member Join Date: Jan 2015 Location: boulder, mt Posts: 14 Likes: 0 Liked 2 Times in 2 Posts	Re: 1967 belvedere claimed as a gtx. Good point about valve clearance, I did not consider that.