I had the same experience with the 284/484 hydraulic cam that I put in my '64 Polara with a fresh 440. You need a looser than stock converter to take advantage of the cam off the line and my converter was stock '64 and tight. It had a great top end once you got over 60, but below that DOGGY down

1986 Dodge Ramcharger 440 2wd, Bracket Racer Under Construction
1998 Ram 2500 QuadCab, new daily driver.
2008 Honda Element
2014 Carry-On 7x14 Cargo Trailer