Yes I was using wather/meth injection but since I removed the blower (6 months ago) and engine is otherwise stock I don't use it anymore.

Bottom end: is there a way to check main and rods bearings without removing the oil pan? Would they be really noisy if they aren't OK?

Removing the heads on a F-Body is such a pain that I'll probably prefer to drop engine + tranny. So checking for other things will be much easier.