If the motor is a 66 it wont be a 235,its probably a 230 or a 250. You might want to look at big trucks with sixes as sometimes they had a front mount and two rear mounts like the older cars and trucks,you probably will have to make side mounts for that motor and if it is a pre 63 235 it should have a plate that mounts behind the timing gear cover that can be drilled to use the front mount in the 53. If you want a easy swap use a 54 to 62 235 or 261 as it will bolt in but you will have to buy a shortened water pump for the 55 to 62 motor or shorten the shaft yourself. Jeff