Well, just looking at them, it seems like the Series 1 and Series 2 3800 use a very similar head setup. The ports are in the same spots. The Series 1 3800 engines I am talking about would be the 1991-1994 engines that had the aluminum "Tuned Port Injection" intakes. From what I read, the switch to Series 2 gave it a lower deck height, but I can find nothing about the valve train anywhere as far as specs go. There's a lot out there for the Series 2/3 engines, but the Series 1 has been left out it seems.
I had a Series 1 L67 supercharged engine in a 95 Riviera, and when my brother and mom blew the bottom end loose, I was able to use a 92 Bonneville Series 1 long block (with just the thicker head gaskets for the supercharger application) to put the car back on the road. When I had the heads off the ports were way too different to use a cam like the older Buick V6 engines use that have the offset ports. Later when I took the intake off of a Series 2 engine, the ports looked identical to the Series 1 engines, and so that is why I thought maybe the cam would interchange.
Just looking at the replacement parts online, like cam bearings, they are listed as different between the two. I am sure that the basic structure of the cam is the same for both engines, but not sure which has the smaller journals, and which has the larger.
