Whats the easiest way to tell the difference between a 348 and a 409?
The first thing that comes to mind and the most obvious is the dipstick location. 409 engines had the dipstick on the passenger side and 348’s had it on the driver side. This isn’t a fool proof method however as the oil pans are interchangable. The best way is by checking numbers. There is a block casting number on the back of the block. Use the casting number page to decode these. A more accurate way is by decoding the suffix code from the front of the block. These can be decoded by using the list on the suffix codes page. If the engine is out and you can see the rear crank bolt flange, this can be a good way to tell the difference. If it is round, it is a 348 and if it is “D” or bell shaped, it is a 409. Back to the top Q: Was there really such a thing as a 409 wheel? A: No, there is no such thing as a “409” wheel. The standard wheel was a 14X5 for cars and the standard for wagons was the 14X6JK wheel. The 14X6 JK wheel was optional on any model. 409 cars did require the 800X14 inch