I read somewhere that Hooker plates will work with the F body pan with only a small notch. Do a search on ls1tech.com in the conversions and hybrid section. Those guys over there have tried just about every combo.
Another option might be the CTS-V pan with Hooker plates.
I did manage to install the LS1 with a stock subframe and a unisteer rear mount rack and fit a stock Fbody oil pan with no mods to it.I was told it wont fit but had to try it for myself.Im stubborn that way