Well if youre already that far into it then from what i understand the FWD Series II is able to bolt up to the 4L60E because both 3800s had the same bolt patterns. I'm just not sure if the Series I is compatible, but the only differences i know of are a shorter deck height, revised cylinder heads, and cross bolted main bearing caps on the Series II.i know i have 2 change manifolds and flip the intake around and i already have the engine mounts besides that it should still be easy, i mean i already found intake gaskets
Just change sensors If he is changing manifolds anyway there isn't much left, everything he is "plugging in" to would be from the CamaroThey are both OBD-1, so I think the wireharness should work. Although the sensors may not be in the correct position.
But yeah, what Smarrt aas saabr said.