I sort of pride myself in trying to find accurate info when people ask questions about the Cummins engines. There is tons of junk and useless info on the net. No need to add more. Yesterday, I discovered something that contradicts info I had taken for truth for 10 years. This involves the HX30W turbos. All info I read showed that turbo came in 4 sizes of compressor and that is still true. Where the contradiction happens is where those various sizes are used . All info had shown the P pump 4bt got the one with the 40x69 mm compressor wheel. Never really questioned that. However, new info shows that is not correct. A member had asked me to identify a turbo which I did. It turned out to be the HX30W 3592313 with the 42x73 mm compressor wheel and was spec'd for 1997-2000 4bt. This started me to thinking since I had always thought that 42mm was sort of an odd duck. So I looked up a couple of P pump 4bt serial numbers on Quick Serve. The 2 I checked had different turbo numbers, 3592309 and 3802646, but that isn't unusual. Cummins/Holset may have 5 or 6 part numbers for the same turbo. When I checked the specs on those 2 turbo to my surprise both showed the same 42x73 mm compressor wheel. Apparently, the 40x69 mm may be an industrial application and was never the road model on the P pump. I guess it's never too late to get the info right.