my own magnum heads, stock uncut, the springs had ~1.63" IH. they coil bind at 1.1" (measured using a vice and calipers)using the hughes 1110 springs, and junkyard retainers from a 2.2L mopar with the magnum keepers, I had 1.60" IH. these springs coil bind at 1.04". when I had the valve job redone, instead of machining the spring pads (which I've heard are kinda thin), I had them sink the valves .030", which netted me 1.63" with my retainers. the hughes spec retainers give you a little more IH, I think. you'd have to measure your own parts to be sure of what you could/couldn't get away with.

I personally am one that feels a lot of people overcam their motor for their needs, and I prefer to speak softly and carry a big stick (be fast, but with as tame an idle as possible). I think the comp XE268 or crower mentioned will be enough cam for your needs (something in the 224@.050)...the bigger cam might make more power up top, but sacrafice some low and midrange that is a lot of fun on the street.

if you plan on following Dulcich's magnum porting article from the may '05 MM, I'd think about a single pattern cam, maybe a like a comp 270H or 280H....