Mate of mine has a early type 3 notch with a rusted out
floor pan, he also has a late floorpan in good nic !!
wants to know can he swap early body on to late pan ??

As long as the early rear subframe is swapped onto the late pan there shouldn't be any problem.

DH

make sure theres at least 6 of you do lift and swap the body there HEAVY as buggary

Ive done 5 or 6 body swaps on Type 3s over the years

can he run the irs box etc ??

He can run the irs box if he
a) welds the rear body mounts in and has an engine which takes the mounting bar
or
b) welds irs pivot boxes into the swingaxle sub frame