My name is Bob- I am the mopar guy that worked at Allstate Carburetor- I am no longer there- They forced me out of my job 2 yrs ago. I was the only high performance knowledge that the company had. I hope your street avenger is not the one they are currently selling with down leg boosters. That booster in the 670cfm mainbody is going to be way to sensitive to air flow. It will over come the off idle stumble because it will be to rich and over fuel the transition area but it will also consume way to much fuel and kill the life of your spark plugs. They are still trying to navigate without me.. My backround is indepth and extensive- all R&D, product developement and recalibrating that was performed by Allstate Carburetor was done by me... Never by Jim- Now he's doing it on his own with no backround knowledge. I tested this down leg booster in a 670 cfm mainbody on a car with O2 sensors in the exhaust and it was Dead on RICH no matter what I did to the carb. It is a definate NO NO.. Shame on Allstate Carburetor for selling product that in NOT 100%