[GTO-relic]

CE metering rod is the richest long power tip rod originally made by GM for any quadrajet, meaning the power tip starts flowing maximum fuel at 70-80 degrees of throttle opening. The dimensions on it are .135-.096-.041" long tip.

CL metering rod is a long taper rod that is on the lean side at .135-.108-.067" also with long power tip. It will reach the power tip at the same time as the CE rod, but has a .026" larger tip. that would be like jetting down about 4-5 jet sizes.

a good approach would be obtain as many of the long power tip rods as you can find, and use them like you would use jets in a Holley. From leanest to richest they are:

DD-.105" (leanest secondary rods GM ever made for Qjet, period)
BS/CZ-.095"
CG/AS-.077"
AT/CL-.067"
BZ/CX/AY/AZ/CD-.057"
AU/CV/CK-.053"
CE-.041" (richest long power tip rods GM ever made)

keep in mind these are metering rods, the smaller size is richer.

there are medium and short taper rods that are richer than the CE rod, but they'll delay the power tip to wider throttle opening point. the richest triple-taper rod GM ever made, was a BV with a .030" short tip.
so you can take ANY rod, turn the tip down in a drill or mini lathe to .030", and have the same WOT function as the BV. or...cut the tip off, and you have the richest metering rod, because the tip is completely gone, and the secondary jets have no restriction at WOT at all, like the AD rod.

if you're racing, you can just REMOVE THE RODS AND HANGER. we did. it works. you can also remove the primary power piston rods, and just run jets. I did, it worked.

the limiting factor for a Qjet carb is, beyond a certain point, the single needle valve can't flow enough fuel to keep the bowl filled. at that point you need a dual feed, dual fuel bowl carb, like a Holley, or Carter Competition Series, etc. I did reach that point, and had to bid the Qjet goodbye. If I had run 1/2" fuel line from the tank sock to the carb, or a fuel cell up higher in the trunk, I may have been able to cure that problem...instead I threw the towel in on the Qjet. The engine would just suck the Qjet fuel bowl dry, even with 2 fuel pumps, an electric pushing into a mechanical. I was running a '70 Buick 800cfm center, '69 Pontiac 428 baseplate, top. Back to back the 800 center was worth 3 tenths, and a phenolic spacer was worth another tenth. 4 tenths difference between a flush mounted 750 Qjet, and the 800 center Qjet w/spacer, on a bone stock 400 RA IV cammed fresh motor, with iron intake, #12 heads, headers, 3640lb w/driver, automatic street car. Later on with the bigger motor, dropped a Holley 3310 on the motor, fuel starvation problem instantly solved.

A medium power tip starts at 80-90 degrees throttle, and a short power tip starts at 90-100 degrees throttle. it's a good starting point. there are many richer metered rods at WOT than that, but they are medium and short taper, meaning they'd delay the fuel flow to wider throttle opening points. the richest of all was the AD rod, which had no power tip at all. i.e. at wide open throttle, it flowed through the open secondary fixed jets with no restriction, into the secondaries. you can make any rod into an AD rod, by grinding the tip off.

FWIW, if you have enough motor, in the 1/4 mile the metering rods in a Qjet don't even matter. 25 years ago we were at the track with a friend's race car, running a 428 Pontiac. It was running 10.50's with a Qjet. He changed the metering rods a few times, but it didn't make any difference. I suggested simply REMOVING the rods and hangers, and do a test run. it ran 2mph faster, and 2 hundredths slower on the next run, with no rods or hanger at all.

you want to meter the secondaries on a Qjet to give the engine all it's got as soon as it's opened, provided that's not too rich for the CID, cam, intake, heads being used. Drive around part throttle on the primaries and get the sharp throttle response, and good drive-ability, mileage. In a way you can think of the primaries as the idling and city/highway cruising mileage carb, and the secondaries as the power carb.

the vintage Carter Competition Series 1970-74 carbs were a Qjet on steroids with dual floats, dual float bowls, and phenolic center section. If you like the spreadbore design and Qjets in general, find the vintage Carter Comp series and purchase it, and tune it up. you won't regret it. it's identical in venturi, throttle plate design to a Qjet, just much better fuel delivery, and about 50cfm more flow, i.e. 850 cfm. They were advertised as 1000 cfm when new, but that was stretch advertising. it will support a higher level of horsepower than a Qjet will, due to having dual needle valves, one per side, but with the same street driving manners.

keep in mind this is relates to what hanger is used. a B hanger pulls metering rods out of the jets in secondary about .095" further, than the leanest letter V hanger. When I was using, building, selling a lot of Qjets, back in 1982-1998 era, I would only use B-C-D-E-F-G-H-I-J hangers. those are the richest ones made, in .005" lift increments, from a B with .520" drop, to a J with .560" drop. You can just bend any of them to the B dimension. If you use a V hanger with a .615" drop, it will negate the effects of the richest AD rod to some extent, because it will keep the metering rods .095" further down in the hole, compared to a B hanger. so....I'd just avoid the lean hangers altogether.

NHRA Pontiac SuperStock 400 racers used to run a J hanger with an AX rod with .040" short tip.