Seems like what I have read, It will fit. the bolt pattern for the 240 up to 83, last year, is the same. The 617 engine is also the same bolt pattern.
As far as doing the swap, there is a ton of DIY write ups on this subject. I did this swap a while back. most all of it is plug and play except for shortening the shift rods, DL and balancing the FW.
this thread is from a couple days ago.
http://www.peachparts.com/shopforum/showthread.php?t=302284
Where are you located? fill out your signature etc...... maybe someone close to give you some help.
Charlie