This is an overlooked detail when replacing a 283 with a newer small block chevy. 307, 327, 305, 350, 400. etc all have a larger 7/1620 threaded crankshaft snout. The early 283 was 3/824. The flywheel forward Chris Craft 283 was specifically drilled between the crankshaft snout and #1 main journal to provide engine oil pressure to the transmission planetary. You might think that it's splash lube since it's part of the crankcase, but if you overlook this very important step your transmission will last about one hour and blow up. These Paragon 25XE transmissions are getting hard to find parts for. If you are running a hydraulic transmission such as a Paragon HF 7 or Velvet Drive then you do not need to worry about this situation. This is only for the mechanical 25XE gear. This 283 was replaced with a 350 long block and the person who switched it over didn't realize this situation. Thankfully there were a couple other issues with the cooling system that prevented this boat from running too long so no major damage to the transmission was found other than the front needle bearing was starting to come apart. Graymarine 475, 620, 100, 109, 136, and other engines are similar to this as well. It's an easy step to overlook and I wanted to document it to prevent this from happening. This also applied if you are swapping in a different 283 crank that was not used for this setup. This hole must be drilled!