Anyone here used the hellcat main bearings in a 6.4 .

I have not and will share an idea.

The Hellcat bearings are probably a harder compound to deal with high cylinder pressure and rod loads. Harder also means less forgiving (dirt & clearance tolerance). If the "regular" 6.4 bearings do OK for you I would not change. If you need the tougher bearing, be careful.

are you asking if any one has modified a Non Hellcat block to use the twin oiling oil Bearings?

Yes.

Just trying to find if theres any benifit using them, and if they are a direct fit.

Benefit= not sure, if you mod the main bearing saddle and add the grove from the main feed to the 2nd hole, I say yes.
just installing and not adding the extra oil grove, I would think no, but have never tried it .

They were a little cheaper when i looked , and i thought if there was a benifit, why not . thanks for replys.