Solid motor mounts with an LSX? and a couple of other LS questions.

[TonyL]

I've been working with the ONE guy who's pulled off installing an LS1 in the stock location in his Corvair. He tells me that you cannot run a solid motor mount to an LS engine because the knock sensors view the vibration as knock, and it screws up the timing. I cannot verify this with my google-fu. So I figured you guys would know.

Is there any truth to this?

also, he says you can run an LS motor with no return line to the fuel tank. Is this so?