Won't get it in there without modding the sump.....Not a chance. You need a reverse sump with the well at the rear. You *might* get it in there, but you will never get the auto in there and even if you did, the driveline angle would be terrible. You will flog out front uni's in about 5 minutes.
Calaber: To fit a V6 into an early girl, it needs the same basic mods as fitting a Chev. That is, cut the crossmember (which is an engineering requirement as it allows the motor to slide over the crossmember in a front on hit) and reinforce it, convert to rack & pinion steering and have a reverse sump that puts the well at the rear (unlike a Commodore sump which has the well at the front).
1 other thing, in Vic, you will require a chassis kit to get in engineered with the V6 in it. Although, in NSW, i don't think it's a requirement. Not sure on the other states.