The t3 turbo's on the earlier cars have a flat flange the same as the ford t3's so need a gasket whereas the petrol volvo t3's had a circular indent and a raised circle on the exhaust manifold, the rs escort t3's have the same A/R as the volvo petrol & diesel ones ie .48 & .42, one of the model years, 85 i think had a .52 compressor, (technical information passed to me by foggy james who like ravennexus is a mine of odd bits of volvo information). I'm currently having a 90+ exhaust manifold skimmed flat coz i've got an uncracked turbine housing from a volvo diesel t3.