the main issues I've had with edelbrocks is calibration. I don't understand the reasoning they've come up with here but I suspect they're catering to the small block chevy crowd. anyhow, once that has been overcome these carbs are very reliable. I think the real downside to them from an all out race standpoint vs holley is the internal fuel passages size. I run a pair of 600's on a ch28 intake and really like this system. tweaks to the carbs were minor but in the end the best intake system I've run on a 440. a friend has an 800 avs on a 427 chevy and that thing took some radical changes to straighten out, but the end results were surprisingly good. I think the 650avs2 I a good step forward for the smaller engines. it's all about the cruise mode. I've found any off idle transition issues to be more related to idle af/ratio and too large squirter.
I wouldn't buy any of the 500cfm carbs; especially with the extra costs. they're just 600's with a screwed up primary booster and the dual quad "jetting" is for edelbrocks dual plane intakes and irrelevant for your tunnel ram. don't get caught in the cfm marketing game. a carb can't create one cfm.
I just purchased 2 500 Performer carbs for my 360 and Street Tunnel Ram. I see the AVS2 is listed in 500cfm and I inquired. But the release date and thus shipping date gets closer and then gets pushed out time and time again. I was told by a Summit tech the AVS2 500cfm carbs are not calibrated for dual quad apps like their Performer brethren (added $$ for me to calibrate down for dual quad apps.) I believe because chevy is the most popular and most sold the Edelbrock carbs are calibrated to work optimally on 350 and 454 builds. But in this day and age a small block is a 400plus cubes and a big block is 490 plus cubes.
