I think you need to double check your flywheel, as ALL Pontiac flywheels from 76-81 weather it be a 301 or A 400 has the smaller register bore as the end of the crank on the later engines were cut smaller to. The flywheels with the larger register bores are for the 75 & eairlier engines. If you have a flwheel with the small register bore you can have a quality machine shop open it up to the larger bore but make sure it's a quilaty shop because it need to run true. Also always check when you are looking at Pontiac cranks that they are drilled at the end to except a piolet bearing, some of the Pontiac cranks didn't get bored out in the end to be able to use them for a stick trans. Not all the cranks got bored for that. Most of the cranks that didn;t get bored or the ones that have the bigger chance of not being bored were the early 70's cranks. It was a cost savings thing.