does anyone know why a convensional small block chevy solid roller lifter will not work in an LS style block ? I just compared the normal Lunati solid roller lifters with the LS1 style and they look the same so I measured them quick with a caliper and they measure the same except a small difference in the height.

Before I get people recomending to stay with hydraulics I have a 427ci engine with cnc'd C5R heads and it needs to run 8800rpm to make peak power.

 

I think it has something to do with the oil passages, but I'm not 100%. Usually, tie bar won't clear either.