I just put a used 625 Street Demon on my 75 F250. 351M, Weiand Action plus, GM style HEI 20* initial and 35 total in by 3000. Exhaust manifolds. I THINK it MIGHT have the Melling, TRW, Elgin, "everybodys" grind that's like 204/214 @ .050, but on a Ford the lift is more because of the 1.73 rocker ratio. .484 and .512. Anyway, I got the carb in a trade. It needed some repairs. The secondary air door spring was broken. Thermoquad air door spring fits perfectly. Put a kit in it. Cleaned it all up lookin like new. This thing runs like a bat out of hell now. When that secondary door opens, this big old truck moves. Anyway, I am noticing something a little different from other carburetors and wondered if others running these noticed it too. There's "not a lot" of the primaries. In other words, the primaries have a kinda short travel. The secondaries come in pretty quick with the pedal travel. I kinda like it. Anybody else notice it?