Any thoughts or things I should know...never rebuilt a carb before...

 Guy dong the dyno said I was running WAY rich and should put in smaller jets...  umm, how do I do this??


 

Jim , perhaps a leaking power valve(s) ? that can cause to rich ! the jets are under the bowls in the metering plates , each side. Normaly the jets factory installed are about right.The power valve(s) are next the jets. Gaskest are 're-usable' if new , the first time i opened the carb all were 'glued' , even had some work to clean the surfaces !  

Also take care of the gasket under the power valve ! , i had one broken ( crack in it ) in tensioning the valve so was also too rich testing engine. And  till you find that....    

the gaskets between metering plates and main body are different in case there's a pumper on that side or not. ( with pumper there's a pipe passing trough which must be sealed by that gasket. )

I had the first time wrong gaskets....

And in de base plate there's eventualy that very tiny litle on-way valve to protect your power valve against back-fires.You can see it on the underside of the carb in the channel providing the chamber with power valve the needed vacuum.

Also easy done is checking the gas level in the bowls trough the sight holes , by turning the bolts on top.Let the engine idle with the sight holes open but be carefull with the bolts and closing counter one.Screw them almost together , as when you unscrew the counter top nut to much there's a lot af gas leaking ( fuelpump pressure ! )  and in any unpredictable direction... so with hot headers... also provide some clothes near the carb as when you're fuel level is to high there will be leaking some out of the sight holes , but this is at atm. pressure.( not pump pressure)

good luck.

 

 

I always felt that the Holly carb. was about the easiest carb you could do. I guess that might depend on which bowls you have, the xtra capacity high perf bowls are easier with exterior float level adjustments. The main jet change over is separate from a rebuild. They don't come in the kit because you would have to choose the size you want after reading the numbers on yours.I believe those are found in the metering body between the bowl and the carb body, of course there are a lot of models these days.I don't think you'll have any problems at all, not near as tricky as the Rochester. Let us know how that turns out for ya.  Good luck.

Norbert hit on a sore spot for me. In my many years of rebuilding Holleys, I have never gotten the correct bowl, or metering block gaskets in a kit.
If you can get a genuine Holley kit, do it! On the top edge of the choke housing will be a number, called the "List" num. That is the Holley part #, and you will need it to get the correct kit. If it is a GM issued carb, it will have the GM # under the list #.
You may be running rich, but, you have to know what size jets you have before you can get replacements. Be conservative on sizing. Don't go too far at one time. If you have #76 jets now, just go down to a #74, and then a #72 if needed. BTW, the jets are numbered(stamped) on the sides.
I think I have a Holley or three laying around out here, I can take a few pics, if needed.

Pics would help a BUNCH...  I'm really flying blind on this one.