Depends on what type of 3.8. Mid 60's to 89 rwd 3.8 (include the 79-85 Riviera) have the standard BOP pattern. Some of the 83-85? Century models used this in a fwd configuration from what I understand, but dont quote me there. The fwd 3.8 introduced in 1985 or 86 has a bellhousing that is the same as the rwd 2.8 V6 and other rwd 4 cylinders. It is much more compact for fwd applications. The "new" 3.8 is actually called a 3800 and shares nothing with any of the ones above except displacement.