Let me preface my question with the statement that of all the years I've dealt with Q-jets and Holleys, I simply prefer the Edelbrocks because I've always had good luck with them, so I'm going to stick with it. I'm looking at the Performer series, but I am unsure of getting the 600 (1406) or the 750 (1411). Or should I step up to the AVS, which has a 650cfm model (18069) I read in another thread that a guy didn't have good low-end with his 750, but he was also running a single plane intake. I will be upgrading to a Performer intake at some point soon - but the carb comes first because my existing Q-jet is hemorrhaging gas. The engine is stock, and all I'm really looking for is to pick up a little performance - mileage really isn't an issue where I live. Thanks in advance for your input!