I believe there is a spacing issue if you run the crank sensor in the factory location from your L61 to the LE5.
I remember reading about that on here, ZZP has a spacer they made to fix this issue, they use it on their 2.4 stroker motors, not sure if its for sale by itself tho.
My head is shaved around 0.005", and I clayed my valve clearance, and with my Comp Stage two cams, and no head gasket on the motor when I clayed it, the valves didn't even indent the clay I put on the pistons.
So there is lots of room in there.
Mind you out of all the guys that built a LE5 hybrid on the JBO I think im the only one who didn't have theirs blow up yet....one from an over boost issue, one from a valve snapping off.
No issues on mine yet tho ***Fingers crossed.
LE5/LSJ Turbo Hybrid, 15psi, 11sec 1/4 miles....Sleeper.