1966 gmc
I bought my 1966 GMC Truck in 1982, MY 2nd vehicle I bought.
30 years later in 2012, I still have my 1966 GMC Truck with the orginal 305 V6 motor, with over 337,000 miles on it as I have not done anything to the motor except adjust the valves and change the seals, change the starter, carburetor, water pump, fuel pump, and took the oil bath air filter out and put in a standard air filter.
I have done standard tune up's (Distributor Cap, Points, Condensor, Spark Plugs, Gas filter every 10k or so. Changed the oil more often than recommended with using Slick 50 at least 10 times in the oil changes...
THIS MOTOR is very strong motor, starts everytime, unless something external to the motor is wrong. Gas mileage is not the best as about 15 to 16 mpg, but RELIABLITY, and this motor is # 1.....
This is one tough motor as I lived back East in the 1980's and moved back west in the 1990's with a 4,000 trip across the USA in this truck...
I had a cousin who told me he had this motor in a Jeep 4 wheel drive and wanted a different motor in it because of gas mileage, and tried to blow the motor up, by 4 wheeling the hell out of it, and the motor would not blow up, they ended up just taking motor out he said..
ONE TOUGH MOTOR MAN !!