[Jay H]

How do the two compare? I know the 6.1 has a forged steel crank, not sure what else is forged if anything on the 6.1. What about the 6.4, Does it have a forged steel crank or a cast iron one like the 5.7?

 

[Red Barron]

How do the two compare? I know the 6.1 has a forged steel crank, not sure what else is forged if anything on the 6.1. What about the 6.4, Does it have a forged steel crank or a cast iron one like the 5.7?

6.4 has a forged crank and cast rods and pistons. Per Henessy they say the 6.4 is good for 600HP or 7PSI of boost.