Carb Clarification and help

SS427 · 10-08-2016, 10:37 PM

Can someone please help me with what legal modifications can be made to a carb in stock? The carb is going on a 402/375 Nova that uses the Holley 780. I have not been able to locate any of the info for stock, just superstock and modified. Thanks in advance.

Alan Roehrich · 10-08-2016, 11:14 PM

You can add a secondary metering block, and you can use bigger float bowls. You can modify the metering blocks as to how they meter fuel (most use a 2 barrel Holley HP metering block).

You cannot change anything that relates to how it flows air.

If you want to modify a Holley for your car, honestly, the best thing you can do is just send it to Jimmy Bridges in Nashville TN, or Clark Holroyd, in California. Their stuff, out of the box, will be so close that you're unlikely to improve on it, and will only need very minor jetting changes. If you're not an absolute expert, you'll spend 5 times as much trying to do it yourself as you would to just send the carburetor to either of them, possibly hurt some parts in the process, and you will probably still not go as fast as you would with their stuff.

10-08-2016, 10:37 PM	#1
SS427 Junior Member Join Date: Sep 2012 Posts: 14 Likes: 1 Liked 0 Times in 0 Posts	Carb Clarification and help Can someone please help me with what legal modifications can be made to a carb in stock? The carb is going on a 402/375 Nova that uses the Holley 780. I have not been able to locate any of the info for stock, just superstock and modified. Thanks in advance.

10-08-2016, 11:14 PM	#2
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,915 Likes: 996 Liked 1,043 Times in 274 Posts	Re: Carb Clarification and help You can add a secondary metering block, and you can use bigger float bowls. You can modify the metering blocks as to how they meter fuel (most use a 2 barrel Holley HP metering block). You cannot change anything that relates to how it flows air. If you want to modify a Holley for your car, honestly, the best thing you can do is just send it to Jimmy Bridges in Nashville TN, or Clark Holroyd, in California. Their stuff, out of the box, will be so close that you're unlikely to improve on it, and will only need very minor jetting changes. If you're not an absolute expert, you'll spend 5 times as much trying to do it yourself as you would to just send the carburetor to either of them, possibly hurt some parts in the process, and you will probably still not go as fast as you would with their stuff. __________________ Alan Roehrich 212A G/S