I have this really nice and well taken care of 1997 monte carlo ls and I have been planning for months on a L67 engine swap out and I have finally bought the engine and it’s on its way right now, but I have a couple questions. #1 do I need to upgrade the suspension to support the engine weight or should I leave it alone considering the Z34 came with the 3800 in 1998-99. #2 do I need custom gauges for the Instrument cluster and if so, where do I find them.

 

What year and car did the L67 come out of?

I have a 96 LS with an L67 swap. The biggest things to consider: it'd be best to get a 4t65e transmission, unless you want the headache of making the current 4t60e compatible (in which case you can use your current axles) but you will need custom axles if the transmission is a 4t65e or 4t65e-hd. Donor car inner axles, your current car's outer axles. You'll need a 98-99 Z34/LTZ 3800 engine wiring harness, and a way to hook up the L67 MAP sensor (I think ZZP sells a kit for it?)

You'll also need a PCM tune for the swap. I'd recommend Milzy Motorsports over ZZP, based on my experience with their respective tunes.

 

No, it's not required. The two engines are maybe only 100-150 lb apart, so cut that about in half per front spring - its a fairly small delta per wheel. Plus the stock fender gap is enormous anyways, so losing a little bit of that is a good thing anyways.

No doubt upgrading suspension is a good idea as the stock handling is pretty bad, but its certainly not a requirement for the swap.

No. You're going to use the engine wiring harness from a 3800 5th gen monte / lumina, so the stock car stuff will work just like it would if it were hooked up in a stock z34.

 

The engine came out of a 2001 pontiac bonneville SSEI.

 

In case you're not aware, the H body stuff has different mounts and such. Not sure how complete of an engine you bought, but you'll need some W body speciifc stuff for it to mount in.

 

I'm fully aware of this and I've planned for it.