The 3.4 came in Camaros.

The 2.8 oil pan, water pump, etc., are used. The 3.4's that we are using are the iron head versions. I think that there are some issues with using the aluminum head versions. Ed MC on the Isuzu boards has all the details on the swaps.

Essentially, what all of us are doing is using the 2.8 intake manifold, bored out to 4.3 diameter and running either a 4.3 TBI or a Holley on top of that.

The GM Performance 3.4 with a carb is rated at 160 HP.

I think that I was the first to do this swap, but others have done a cleaner version since and Ed has all the documentation and is a wealth of knowledge on the topic.