View Full Version : Carb Rebuilding: Need Help with Needle and Seat Size

09-20-2007, 10:59 PM
Hey guys, I just about have my Holley 4150 Carb all rebuilt and back together. I ended up buying the Holley Tech Manual and did it myself. A bit easier than I thought and also saved me bout $100 from bringing it in.

I ran into a few problems while doing it though. The power Valves included in the kit were sizes 6.5 and 7.5 so I had to go buy the 2.5 at the parts store. The gasket for the primary metering block was also missing 3 holes it was supposed to have in it so I had to make those myself. Other than that everything else in the kit is a direct match.

I also recommend to those of you that have never rebuilt a carb and want to give it a shot that when you tear off the old gaskets to keep ALL of them so that way you can match them up to the new ones to make sure they are exactly the same.

The Needle and Seat size is a 110 that came with the kit. The ones I pulled out just had the letter "H" on them so I'm not sure of the size. Does anyone happen to know the correct size that is supposed to be in there? I looked on the Holley website and they come in .097, .110, .120, .130, and .150. Looking closely at the pics on the website the old ones almost look like they could be a 120 or 130, but again I don't know. If anyone could please help me out I'd appreciate it!

09-21-2007, 06:20 AM
Can you take a pair of calipers or an 0-1" micrometer and measure them? That may tell you.
The 110 is basic general purpose.