how to tell a 750Qjet from a 800 Qjet

Lonnie Cox · 05-24-2013, 09:19 PM

please tell me
My carb # is 17056502 do you know if this is a 750cfm ?

Rob3105 · 05-24-2013, 09:39 PM

Look through the primary venturi and there is a ring/step on the outside of the bore. The 800 has a narrow ring and the 750 is wider. If you have both sitting side by side it is easier to tell. After you look at enough of them you will be able tell easily. This is the easiest way to tell quickly but you could measure the venturi as it is called out in the NHRA specs as 1.093 for a 750 cfm.

Rob Turkal

Mark Yacavone · 05-24-2013, 09:41 PM

Lonnie, On the 1.21 venturi carbs, the top screw that's inside the choke horn, will just about fall through between the venturi cluster (booster ring) and the outer wall. On the 1.09 it won't be close.
After studying that area, you'll be able to tell be the shape and curvature of the venturi wall.

Lonnie Cox · 05-24-2013, 10:02 PM

Quote:

Originally Posted by Rob3105

Look through the primary venturi and there is a ring/step on the outside of the bore. The 800 has a narrow ring and the 750 is wider. If you have both sitting side by side it is easier to tell. After you look at enough of them you will be able tell easily. This is the easiest way to tell quickly but you could measure the venturi as it is called out in the NHRA specs as 1.093 for a 750 cfm.

Rob Turkal

My carb # is 17056502

GTX JOHN · 05-25-2013, 06:01 AM

If you hold primaries open.......Is there not a Flat area on. 800 where it is
perfectly round on 750 outside walls?

BTW. I have a supply of Edelbrock Replacement Q jets all # and sizes.

05-24-2013, 09:19 PM	#1
Lonnie Cox Junior Member Join Date: May 2010 Posts: 88 Likes: 0 Liked 0 Times in 0 Posts	how to tell a 750Qjet from a 800 Qjet please tell me My carb # is 17056502 do you know if this is a 750cfm ? Last edited by Lonnie Cox; 05-24-2013 at 10:01 PM.

05-24-2013, 09:39 PM	#2
Rob3105 Junior Member Join Date: Jun 2007 Location: Midwest Posts: 20 Likes: 28 Liked 1 Time in 1 Post	Re: how to tell a 750Qjet from a 800 Qjet Look through the primary venturi and there is a ring/step on the outside of the bore. The 800 has a narrow ring and the 750 is wider. If you have both sitting side by side it is easier to tell. After you look at enough of them you will be able tell easily. This is the easiest way to tell quickly but you could measure the venturi as it is called out in the NHRA specs as 1.093 for a 750 cfm. Rob Turkal

05-24-2013, 09:41 PM	#3
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,416 Likes: 2,582 Liked 4,453 Times in 1,694 Posts	Re: how to tell a 750Qjet from a 800 Qjet Lonnie, On the 1.21 venturi carbs, the top screw that's inside the choke horn, will just about fall through between the venturi cluster (booster ring) and the outer wall. On the 1.09 it won't be close. After studying that area, you'll be able to tell be the shape and curvature of the venturi wall. __________________ We are lucky we don't get as much Government as we pay for..... Will Rogers

05-25-2013, 06:01 AM	#5
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,530 Likes: 2,222 Liked 1,809 Times in 572 Posts	Re: how to tell a 750Qjet from a 800 Qjet If you hold primaries open.......Is there not a Flat area on. 800 where it is perfectly round on 750 outside walls? BTW. I have a supply of Edelbrock Replacement Q jets all # and sizes.