This topic is about the new gm 3500 or 3900 block (lx8, lx9, lz8, lz9 use the same block) and how to mount it (sorry no short star). The description will be under the pic. Not too sure how to put it, so if I have left something out please ask about it! I have used the eng/trans out of a 2007 impala 9c1 copcar (lz8 with DOD and VVT). The electrical How To will be up after I have finished everything. The info for the eletrical I am using is from the Mitchell manual.



The lump for the pipe in the 2.8 needs to be cut down for the new ac compressor




Rear driver mount is 4t40 upper mount (with a few spacers and a funny bracket thing) with a fiero lower mount



For that mount, the slots need to enlongater towards the passanger side



A bit of trimming needs to be done at the trans for clearance



The front mount is a stock 2.8 with a side bracket to make a second mounting point.


The normal fiero front trans mout works fine



The exhaust routing requires the flange from the impalla, bullet cat obd2 high flow, and a muffler from ebay (abad71camaro) camaro/firebird (its a bit shorter than the orignal fiero muffler). All piping is 2.5", with 1D mandrel (dr.gass was the supplyer) a 2x90 (the u-bend) and a 80(for the flange to cat). the dogs legs are self-made to pull the muffler in.


the trans shifter plate is the fiero one hammered flat (one end is spaced up w/ washers and shortened by cutting a bit outta the middle), works perferctly!


The axls info is on here some where, the same for any 4speed auto

Thats how to make is slide right in!

Enjoy, Matt

I want to say! Excellent work good photos. definitly in depth. Your project looks great the exhaust setup looks good. A++ can't wait to see it running.

Good job Matt, you sure you don't want to stop and switch to a 3800 : o). I'm assuming you intend to run the OE PCM, that will make this swap very interesting. You will have to be careful if you intend to, or have made any modifications to the engine because it could affect DOD and VVT calibration.

[This message has been edited by Joseph Upson (edited 02-07-2011).]

I have to say I commend you for posting this topic. This will definitely help people make new decisions regarding which engine they want to swap.

On a side note I'm doing a 3400 LNJ swap which might be very similar mounting and am curious what your doing about an upper engine mount?

Its been on stands since May 2010, so I cant wait to get it running either. Of the buick v6; I did think if switching to something easier, but I have to say the 3300 cough my eye over the 3800. The 3900 is all stock, the idea of this build is fuel economy. Also, I am keep the stock ecm/tcm/bcm/gauge cluster, and the abs computer has been modified (but its not needed) so I don’t get any abs/traction errors on the DIC. When thinking of power plants, I wanted to keep the v6 (being its a gt) and 4-speed auto. I thought VVT and DOD would help more for fuel than any other of the v6's currently out. That brought the list of power plants to the 3400, lx8 and lz8 that I thought were good ideas. The lx8 I could not find, but the lz8 was in all the 9c1 impalas, so it was easy to find. I am hoping that gm keeps making parts for the lz8/9 to keep the prices of repairs down and increases the knowledge of the motor. The lz8 seems like a great idea; the fuel cruising is that of a 1.9L 2600lb car, but I can get a 5ish sec 0-60.
Matt