i have a 1974 cambell daycruiser with a ford 460. we recently replaced the pistons cause they were shot. before we took the motor apart we had spark. now that the engine is back in the boat and completly put back together.. we arent getting any spark... what could this be? we just bought a new coil so thats not it. could it be the ground wire or the distributor?? any suggestions would really help. thanks