i have a set of factory lt4 roller rocker arms <1.6> . ? is will they fit under stock lt1 valve covers?

 

yes sir.. If anything you just have to pinch the mounts a little where the center bolts go through

 

Problem being true LT4 rockers are made for the production LT4s 10mm rocker stud NOT the 3/8th stud the GMPP heads and the LT1 heads use, so while the valvecovers are not a problem they still won't work on LT1 heads IF they are indeed production LT4 rockers.