I put a 340 in front of a 904 in a 69 Charger (originally had a 318), and added a 3:55 rear gear. Can't say how long it was going to last, but it sure was fun the summer I put it together and beat the crap out of it. The kid down the street wanted that 69 Charger body way more then I did and he became the owner of a 69 Charger with out the motor and trans. The motor eventually ended up in my dirt track car. The trans probably got sold.