Well I discovered that the 96 97 z34's had the 4t60-e tranny and im pretty sure that the mounts for the 3.1 3.4 3400 and 3800 are all the same on the W body right? The 3.4 i was looking at is a 96 so I would not have to change my tranny for the 3.4 like I would the 3.8. Plus the 3.4 is $200 cheaper than the 3.8's around me. I would Like to do the 3400 swap because its the most direct. If all I really need for the 3.4 is the wiring harness out of the 96 how bad could it be? If you dont believe me about the tranny you can google a vin for a 96 z34 and check it.

 

All the engine's don't have exactly the same mounts, but if you take the mounts from the engine, and it's a 1st gen or 1.5 gen w-body (for the DOHC), then you will be fine. Also, I never said that the 96 Z34's didn't come with a 4T60E. In fact, all 1995-1996 Monte Carlo Z34's came with a 4T60E.

Now, back to the 3.4L DOHC that you're looking at, how many miles does it have? If it's high at all, it's not worth it. Replacement parts are going to be harder to come by, and more expensive too. That's another reason to get a 3400 or a 3800. Honestly, the only reason that I see you do a 3.4L DOHC swap is because it's unique. In the long run, you will spend more money on that engine then you would on a 3400 or a 3800.

 

It's $300 with around 88,000 miles on it. considering my 3100 had 200,000+ when It died, I think that's a fairly good deal. I'm more worried about what its going to take to make it compatible. I read somewhere that the ecu could be used from the 3100 the gear ratio was slightly different in the 3.4's 4t60 but not a terribly noticeable amount. 300 for the engine and 45 for the harness doesn't seem like a bad deal to me.

 

You'll need the PCM for sure. Timing, fuel delivery, etc are all COMPLETELY different on a 3.4L DOHC then a 3100, so that's why you need the PCM. IIRC though, the tranny's should have the same gear ratios. Can't remember for sure though.

 

Okay so the engine, ecu, wiring harness, and possibly mounts? that should be all I need? that and time.