Porsche had a long standing relationship with Zenith. Zenith carburetors powered many 356s before losing ground to Solex and Weber as the 911s and 912s came along. But then they made a return to favor on the early 70’s 2.2 T motors before fading from popularity like bell bottom jeans. Which is exactly why I’m interested in them. I love being out of style. No, not exactly. Talk to three different people and you might get three different opinions on Zeniths over Webers: over complicated with three fuel accelerator pumps, hard to tell the variations in manufacturing over the years. But you may hear durable and hold a tune, work great on the 2.2s they were intended for, love the three accelerator pumps. Then again, they aren’t as versatile as Webers and not many modifications or setups can be made. With all those opinions on the table I decided to put a set of Zenith carburetors up on mine to find out for myself.
Currently, I’m running Weber 40 IDAs on my 1971 Porsche 911T. They came with the car yet need to be torn down and given a once over after a few years of use. I’m not sure what jetting they have yet was pleased with the way the car drove initially so I didn’t bother to dig into their details. With the Zeniths, I can start from scratch, set them up for modern fuels with bigger jetting and dial them in against the Weber performance, seat of the pants though it might be. All the jetting and many parts for Zeniths are available from alfa1750 on eBay. I’ve read on Pelican forums that someone is also machining new bigger venturis than the standard 27mm. Venturis were one of the biggest factors holding Zeniths back from draining the big juice in a large or modified engine. You still won’t want to run them on a 3.0 liter SC motor so I’ve heard but maybe a 2.4 or at least the 2.2T which is all my jeans are going to be sitting in.