Thanks Patrick. It appears that the PT61 is not the same wheel sizes as the old school TE61? Both gnttype and the chart on turbobuicks.com suggest the old school TE61 had the same compressor wheel as the TE60.... just different exhaust wheels. On your chart, you list different inducer/exducer dimensions for the TE60/PT61. I assume the newer PT61 is using the new tech GT wheel comparable to the GT6152 that Limit sells? There is not alot of technical info (at least not near as much as I would expect) available on the net for the various compressor wheels and turbine wheels.... or shaft and housing (compressor and turbine) info. You have to take a piece from over here.... and one from over here.... and yada yada..... combine it all together to make anything of it.......