To be honest I doubt any modification work has been done on it, every bolt seems to be welded on as tho the engine has never been apart. while were on about the v6, is there anyway to improve the air flow through the 4 into 6 inlet manifold, as I believe its a major restriction?

Also do you know of a good supplier of tuning and performance parts for one of these lumps? my rocker shaft looks a little scored up where the rockers have been going at it, i think there has been an oil flow problem at some point as scoring of the shells, big ends and little ends seems to be quite common, so i figure stick a hot cam in while its in pieces.