Dual Quads with 450cfm or 600cfm?

[Michael C Henry]

I have a pair of the 600 CFM 1850 Holleys on a tunnel wedge set up. I'm on a quest to get them functioning as a pair of carbs designed for dual carb appication. Thruth , I can't remember ever getting into it long enough to notice if the secondaries ever opened.
I have the Mallory HyVI and have rev limmiter programed for 6,000 to keep everyting from going south. I still like those flow through aircleaner tops.

[decooney]

In a local circle of friends and different cars, we did dual 450s on a 331 stroker Cobra which worked very well with progressive linkage, then dual 450s on a FE 390 which worked okay (could have been better) as it just did not have the same zip as it did with the single HP 750 did, then a set of brand new and finely tuned dual 550s on my friends original R-Code 427 Galaxy. He really likes this setup a lot, with factory pluged up type exhaust and original exhaust manifolds, these 550s do really well on his original 427. On another guys car he had a set of well tuned 600s in a Cobra. I'm just thinking back on all of these configurations trying different stuff and who was happiest. Knowing thisnow, If I were to do a dual setup on my FE it would most definitely be a well tuned/jetted-down/flowed pair of 600s (or so) Holley's, followed by lots of messing and fine tuning of progressive linkage setups and ratios until it was right. Believe it or not, we were able to get (freeway) 18.1mpg out of my friends 331 stroker Cobra and the motor was right at 430hp running the dual 450s. Another friend setup dual 600s on his Cobra with a 410merc FE. It rips, amazingly well. In each of these scenarios what struck me the most is it took a few times to get it right but once it was spot on, it was really fun to drive in every situation except the 390 dual 450 setup which we never got it dialed in. If I had to do it over again, I'd see a really strong carb specialist before running duals again, it could have saved us some time; I think. Trial and error I guess.