rocker arm ratios

Everyone needs to remember that even with accurate 1.5 rockers, you WILL NOT get the advertised 1.5 cam lift in a small block Mopar. The main cause is the lifter/pushrod/rocker angles which are not "in line". I forgot the numbers, but I think it's at least .015-.020". Probably higher numbers with higher lift cams. Not sure how bad the big blocks are.

.....or slant 6's. There can be smaller losses due to other factors also.
Is the /6 geometry inline or off to some degree?