I'd do it for $500 plus parts
You could use XJ leaf springs. You would also have to cut off alot of the old link and coil brackets.
I have some XJ springs i'd sell for cheap
has the front been sasd ? im doing a $ est. for a cust. now on installing a 80 waggy front on long arms and 4 link rear. i think i can do a rear for a grand or less parts and labor