Are you talking about just the block as a magnum base or more about the magnum heads?
Comp 8043-16 solid rollers are Pushrod oiling and oil the rollers I think your 1008-16's would work as well
custom pushrods
Better rockers (I believe you can use chevy aftermarket for the mag heads)
Better springs (K-motion is what I recently used)
I used a normal LA milodon bronze distributor gear in my 5.9 block
