Just to add what those guys said above. The Series II 3800 L67 and L36 are the same block, just different pistons for sure, and IIRC the crank and rods are the same. The heads are different from the L36 (N/A) to the L67 (L67). The fuel injector bosses are in the heads of the L67 because of clearance issues from the supercharger.
Now another fun swap nugget. A guy that has a modded W-Body car (FWD SeriesII 3800. swapped a L36 short block with the heads, intake manifold and supercharger into a '87 Olds Cutlass. He kept the M90 with the sameway as FWD so he had the T.B. pointing right at the firewall. He had to cut a huge portion of the firewall out to get things to work (plumbing). Also, as posted above, he made his own motor mounts. But, got to use the FWD serp. belt routing (pulleys). The modded L67 ran a best of somewhere in the low 12’s and also noted that he said he got air under one of his tires on the launch. 
Actually I found his page. (would’ve save me some typing):rolleyes: