Difference between solid roller and flat tappet

I have no idea how agressive the lobes on the Howards 260/264 cam i now have is. So dont really know how to compare.
Taking my stuff up to the shop that did the dyno competition winning stock stroke 360 this afternoon.
Gonna look over my shortblock and heads, see if my intake i am gonna use( excellerator) needs milled because heads were a while back etc.