Lifter and cam question

A couple of quick questions.....

I had always thought that small and big block hydraulic flat tappet lifters were the same......but in doing some research I see some manufacturers have different part numbers for big / small block, yet others show the same litter for both......what gives? I believe they both have the same bore diameter, do they have different heights?

Next question, I just bought an Engle he3844bl cam, only used for some dyno pulls, in very nice shape. It only shows very light polishing of the lobes. Does anyone have any experience or reviews with this cam? Will I be OK to install it with a new set of aftermarket lifters and break it in normally?

Thanks!