[Tom Vaught]

Not sure how many Pontiac People read STREET RODDER but I have been a subscriber for many years. Love the old 1930s Ford Vehicles: 32, 33, 34 especially. Think "American Graffiti". But enough background on the magazine.

In the August 2019 issue id an article by Jeff Smith on the Holley #3310-3 4160 4 BBL carb and later - number carbs.

The Holley carb comes stock with two of the Center-hung Float Bowls and a Metering Plate on the Secondary Side of the 4 BBL carburetor.

The Magazine article covers converting the Secondary side of the carb to Dual Metering Blocks. We have covered this topic somewhat in the past.

The article has some nice pictures and Jeff Smith gives a parts list that you can use when ordering from Summit. No real info for people who play much with Holley carbs but the classic look carbs are still my favorite vs the Silver or Natural Finish stuff.

The point being the typical Metering Plate needs to be drilled precisely if you need a greater rear main circuit flow. The once you did the drilling now you need to order a original metering plate if you want to go back to the original fuel flow settings and the Metering Plates are not cheap vs a pair of jets.

So you order the proper Metering Block and now you can swap jets on the rear for a very small cost if you have a box of Holley Jets on the shelf.

The Conversion Kit with metering Block and jets is Holley # 34-13
If you have a "silver" carb then part number 34-13S

Holley also sells a Kit for the #1850 carb.

That being said, I personally look for old #3310 Holley carbs at swap meets and buy a whole carb for $15-20 and use the Primary Metering Block on the secondary side.

The #3310 Primary Metering Block will work great on the secondary and also has the ability to install a Secondary Power Valve. So a couple of extra tuning options with that set-up. And a lot cheaper vs the stuff from Holley/Summit.

But Jeff is trying to sell parts for Holley and Summit.

Tom V.

My next post will cover how to make the mods necessary to make that old #3310 carb into a more modern #3310 "4 CORNER IDLE" VACUUM SECONDARY CARB.