Usually the 301's are in such poor shape that folks often come to your
conclusion. The 301 has a number of very positive attributes though.
It's lessor weight makes for an outstanding autocross racer as it's balance
is nearly 50/50. No 400 powered Fbody has that, they are very nose heavy
and can't handle as well.
All GM engines of the era are overcome by emmisions regs and configs
and as such all are in about the same state of detune.
So, if you really need massive HP, none of the period's engines will offer
that much. The 455 was mighty for it's day, but the cost of making that
happen usually exceeds most budgets. The LS1 and LT1 engine families
are quite impressive as they have all of the big three... gas mileage, HP and
torque, but then again it's a chevy engine and you have just another
hacked up classic that few will want after you.
Most used car venues feature many listings of cheap, hacked up Fbodies,
that might even save you some money as they come pre-hacked with
just about any engine you can imagine.
Joe