There isn't what I would call "extensive" porting.
I haven't seen leaking castings as an issue with stage 6's in general, other than the porous early ones...... But those actually look a little different, so they're easy to spot.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
