google man.. basically there are 2 things u need to know (anyone else feel free to chime in i only know enough for my plans).
1st camshaft duration
2nd camshaft lift.
duration depending on its size basically moves the power band further towards the redline.
and lift is important, because the more lift=more air and fuel can get in...this is what gives people a lumpy idle,...hi lift
for u. u can fit 256d, 8.50mm lift (i think off top of head) without ANY mod's they drop in.
but after 8.5mm lift it is recommended to go better springs and a solid lifter conversion.
also u may have to get the head regrinded=clearance issues.