Hello Garry,
No, the colour coding only applies to the 38A blocks used in the 4.0 and 4.6 litre V8 engines.
The 3.9 litre V8 uses a different block. Even though the 3.9 and 4.0 litre engines are exactly the same capacity, the later uses a long snout crankshaft with larger journals, different connecting rods and pistons, and is a fully cross bolted block.
A 4.0 crankshaft will not fit into a 3.9 block.
Ron.

