I have the original pro-flow rpm with 4V system and have had it in my Camaro since '97. I had to replace the O2 sensor twice and the distributor once. I have the Mallory distributor since '03 and have had no issues. I am tuning it a new SBC 409 engine and working out all of the kinks. The new one looks really cool. As for performance, the car with me is 3800 LBS and I have run 12.69 with a 4 speed S10 and I bogged in 2nd. I am working on that so I will let you know how that works out.