340 cam replacement

71 steel crank 340 with factory 10.5:1 pistons, later LA360 factory heads, air gap, 650 speed demon, tti's 2.5 w/Xpipe, 3k stall, 3.91's in my 72 duster. I bought the engine newly built and together. I was told it is a lunati .480 cam. That's all I kmow. Any recommendations for an off the shelf cam that will give me the best performance with using the springs I have. Need to get running again quickly, so just want to swap cam and lifters..