To save weight, engineers removed some of the counterweights from the 301
crank. This made it the only externally balanced Pontiac V-8 made.
They put a limit of 4500 rpm on this engine because of the crankshaft design.
Since non chevy GM V-8's mostly make their best power in the low to mid rpm
range, the design worked fine. What we have found is that if someone ignores
the restriction, the crank flexes slightly in the middle and starts some bad main
bearing wear that can quickly spread. High revs are outside the power band, and
essentially the damage is really abuse caused by ignorance.
The "other" design limit is the single plane, small channel, high velocity intake system
that was born to get some fuel economy. When they turbo charged the thing, the
intake system was no longer the problem.
Perhaps the largest problem the 301 sees is oil choking in the turbo's oil passages,
destroying a precision turbo built to spin at 130,000 rpm.
Later owners of these cars usually got one with a dead turbo and concluded that
they were dogs... They weren't, but needed an informed owner to take car of their
In 1980, a stock turbo TA paced Indy. All they did was take out the AC compressor,
change rear gears to 2.56 and use shaved tires. To pace the race, the Pace car
had to handle 80-100 mph. That's getting some groceries pretty darn fast I think...