Precizion 818 has a point if you go with an aftermarket condenser it might not fit the stock mounts? You might consider a change to R134a.
some conversions use a different condenser.
R u asking for total replacement of factory a/c from firewall to engine (box & all) ?? if so I am about to pull factory a/c out of my 70.000 mile 87 to go with Vintage ...if this excites you PM me to discuss...........Thanks