My Duster has a pump gas 500" big block in it, 3.55 gears, 9.5" Dynamic converter, 275/60/15 rear tires, and the 557 purpleshaft cam along with Manual brakes. The 557 has plenty of lope and sound, nobody believes it's that small of a cam.

I really want to put 3.23 gears in it and tighten the converter, but it is barely loose enough for it to idle properly in gear. It idles at 1300 in park and 950 in gear, I've played around with everything in the carburetor but can't make it idle lower in park without shutting off in gear.

I'm probably gonna install some 3.23 gears over the winter and go with a slightly taller brand of 275/60/15. If the converter slips too much I'll put the 3.55 gears back in. I drive this car alot, it's a blast, but I've learned that the cam and converter have to be happy together.