I need to get some spare parts together to see if I can get a heat exchanger from a Mustang Cobra to fit my SLK32 amg. From what I can see the fittings on the exchanger and pump are 3/4" and they drop down to 5/8" at the hard pipes. Would this be correct? Or the metric equivalent of course.

 

I just measured the O.E.M. H/E; it is 19mm O.D. & 14mm I.D. (3/4" & 9/16")