sounds like your another aussie, 4.1 x flow would be a from ford falcon, an aussie 6!
look up places like marks adaptors (hope i got that right, as i am still a newbie to the 60 series!), there are planty of conversion kits available from the 4.1 ford motor through to the ford v8's as well as holden v8's and chevy v8's.
i am sure that there are plenty of guys that have done these conversions on the boards here (you can also check out the outer limits forums which is more aussie based, they will know what a 4.1 x flow is!)
and i am sure that you will get lots of tips!
myself i am contemplating putting a holden v8 into my 60 series sfter its registered, let us know how you go!