I can tell you what I did. my r/t with a completely stock '69 4bb engine and exhaust (all original parts, no souped up mufflers or stuff), 3.23 gear, 225-70x15 t/a radial ran a best of 14.01@98.9mph. added a 6pak only and went 13.45@104mph. 103mph was a bad day out. I will say that getting to 104mph was a challenge. I had a twisted fuel line back by the sender that was ok for the 4bbl but wouldn't supply enough fuel for the 6pak. once figured out things began to take off. Chrysler claims a 6pak was between 340-370hp stock.


I have a august 1969 hot rod magazine strip test were an a12 car ran 13.56@105.63 completely stock. I think this is a very good number for a stock a12 because I remember a bunch of them couldn't get into the 13's.


I also have a September 1970 popular hot rodding chassis dyno test on a '70 6pak super bee 4spd. completely stock it made 244hp@4250 rpm. ran 13.95@100.78mph. after dyno tune it made 272hp@4250rpm, ran 13.74@105.63mph.


when I finished messing with my r/t 6pak combo it was making 325hp at the wheels on a dyno jet. 9.3:1 compression. stock valve '906's, hughs/engle 2330 cam, 3.23 gear, same t/a radials and exhaust manifolds with dynomax super hemi mufflers. eventually it picked up 9mph in the quarter and I believe at least 6mph was the 6pak. they are power adders for sure but people screw them up with dumb ideas.