Ran the 284/484 cam in my 70 Chally convertible 4-speed with an otherwise stock 340, had NO assist at idle/low speed. Went with Rhoads lifters and then I had power assist. The thing idled really lopey and ran hard. Loved it except for the low vacuum for the brakes. I would not recommend the cam unless you are going to run a vacuum reservoir or electric vacuum pump for the brakes. Of course this engine was built in 1984 so the cam may be different now as someone suggested.