i recently blew the motor in my 02 Monte, and i want to take this opportunity to replace my motor with one that has more HP. I have been thinking about finding a 04 or 05 supercharged 3.8 to install. I feel this will be the most cost effective method to boost my HP. I need to know if this is possible and if anyone knows what other parts need to be changed to do it, like the computer or wiring harness.

 

You'll need to keep the flywheel from your original motor and swap it over. Aside from that you'll need a PCM file or PCM from that motor.

 

You will need a PCM with a Serv code for the 04-05 Impala/Monte L67 programmed to your VIN number, the 04-05 Impala/Monte L67 wiring harness, and you should switch to the 4T65E-HD trans to help with the extra torque of the SC (and the passenger side axle for the HD trans)

BBEngineer

 

You could also run an engine from a 1998 ( say 98 because the 97 was a bit different) and one from a buick regal.

It wouldnt take much more to put in an l32 either, which came in 04+ grand prixs.

 

First we need to know what engine you blew up. If it was a 3800, you will be much better off- get a series 2 supercharged 3800, drop it in- a few minor mods, and you're set to go. If it was a 3400- you're going to need to find a regular 3800 engine bay harness for your year since that engine was 99% the same as the supercharged 3800 that you're wanting to swap in (then just buy the L67 swap wiring adapter- just 2 plugs).

The engine you are looking for is called the L67- and could be taken out of a grand prix back to '98, along with various other cars. It will be far easier to find a grand prix engine from a 98+ rather than try and track down 2 years of a relatively rare trim of monte. Also, you can swap the trans in as well (especially if your engine blew from abuse).

Technically its a flexplate on an automatic trans

Another option is to just do the HD upgrade (a couple places online sell the parts for this- its just the diff/diff cover/passenger axle- pretty easy to swap) to your current trans, and keep your higher geared trans. The common HD trans with the L67's had a 2.93 ratio. Not sure what your sprocket ratio is, but a lot of the 3800's NA had the 3.29's- which would mean quicker acceleration.

 

apples and apples broseph lol

 

He would be much better off getting the 04-05 Impala/Monte L67 as they came with the l32 internals (powered metal rods, etc)

For the L32, you need to swap the oil pan or notch the L32 lower engine mount and get the Gen3/GenV adapter plate so you can use the older style throttle body on the GenV blower that the L32 has

The only issue there is the 02 tranny didn't have the hardened 4th clutch shaft, so it's advised to either upgrade to a newer trans (with the hardened shaft) and then do the HD upgrade, or go straight to the HD trans

All 4T65E (aside from the 4T65E-HD) in the Impala/Monte are 1:1 sprockets, so an HD diff would indeed yield a 3.29 ratio

BBEngineer

 

I wouldn't hardly say 'much better off', no one has ever had any problems with the normal L67 bottom ends/internals handling power, so its not like there is any strength upgrade there.

Also, are you sure all 04/05 monte L67's had the PM rods? I remember seeing pics on clubgp of an early L32 out of an 04 GP that still had L67 cast rods.

Either way, I don't see why you would restrict yourself to just the monte engines anyways- it would be far easier to find a 98+ GTP.

Definitely agree here- the L32 requires more work- you need the adapter or a N* TB, and then you have to deal with the returnless fuel system too (ie put an L67 fuel rail/setup on it).

I wouldn't be that worried about it, sure it would be nice- but adding the cost of a trans swap also could easily almost double the price of the swap. If he beats on the car, the trans is going to fail anyways- hardened 4th shaft or not- they're just weak transmissions in stock form.

There are plenty of top swapped people running just fine on older 4t65's though.

 

good luck with the swap, hope to hear more, sounds like these guys have plenty of good avice. Trust me you will love the supercharged eninge!

 

The Monte has a 3:05 gear. You could just REBUILD your engine and do the top-swap at the same time, so you have a reliable car.