Finally got the HEI swapped into my 70 K5. GM was giving me fits. The HEI dist for a 250 is a SBC unit with an extension pinned to the end of the shaft to drive the oil pump. Of course, the extension is a discontinued piece. Found one at a dealer in Denver. $26 with shipping for a piece of steel 2 inches long!!!! Took bout 20 minutes to get running, had to dig thru my pile of plug wires to find ones close to the right length, that took most of the time. The old girl runs better, but I still need to rebuild the carb, cause it sat for 3 years. Overall, between my stereo install and the ignition upgrade I'm making progress. Next step, installing the OE radio and below dash speaker I found.