If there are bad rod bearings or valve train issues then they show up when the motor is cold by knocking, ticking, or clunking. Cold start is very important in older vehicles with less tolerance in mechanical wear over time. Hope that answers your question!
Pontiac didnt make a big block or small block , they were large Journal and small journal engines and to short deck engine those being the 301and 265. The 421,428 and 455 are all 3.25 in. main journal and rest are 3.0 in. main journal.
