thats about the best pic i have of my celica engine. you can still buy that manifold through LC engineering but its spendy, you might get lucky and find one on ebay or maybe through a weber retailer for cheap.
the linkage is part of the kit and uses the stock stuff
and as long as you dont have struts this WILL fit in there too
read my wagon build up thread for more pics and fitment issues for a supercharger in a corona
as far as a rebuild goes, if its been that long seals have prolly dried out. tho ive seen a few times where the bolts back out a bit from temp changes over the years, and thats all that was needed to fix leaks.
but if your throwing oil off the main pulley a new seal is needed.