I have a 2001 SS high sport and just found a good deal on a bonneville with a great conditioned engine and supercharger but with a bad transmission. The donor car is a 2000 Bonneville. Just curious about a few things. First the pcm, should i uae the bonneville pcm or the monte's pcm? What are the most common mistakes someone could make while doing this swap? Also what else if anyone knows could I use from the bonneville? Also what are other suggested things to do while I have it all apart? And is there anything I should pull the fuse out of before I swap pcms?

 

I'd just use your current pcm and update the engine tune to L67 files.

The Hbody stuff is a bit more difficult to deal with as there are several differences from a w body l67. The most problematic will be the mounts as I believe they're all different and need to be swapped out for W body stuff. May also run into issues with the oil filter adapter (or oil pan?).

Assuming you've got a 3800 in your car now though, you should be able to swap over your old parts to make it work. The tough one is going to be the passenger side upper as thats part of the coil pack mount. You'll probably have to go to a junkyard to get that stuff off a W car.

Also keep in mind you'll need to deal with the wiring also. They sell an L67 swap harness adapter or you can just make the mods on your own.

In terms of what - maintenance or mods? If the former, what kind of mileage is in it? If the latter, what are you looking for and what is the budget?

 

Have you considered just a top swap? May end up with a little more power going that route..

 

Thats a really good suggestion too. Assuming of course that there isnt a huge mileage difference between the two.

If the price is good enough, you could buy the whole thing and just stash the bottom end in a corner for now until the L36 bottom end either frags a piston or spins a bearing years down the road.

 

Well top swap may be the best option and glad to know I dont have to swap pcms. Earlier today I noticed that the arm on the transmission filter is broken which happened to my first monte carlo a few years back. Ended up buying a tranny rebuild kit and was going to hire someone to fix it, he noticed that and we replaced the filter and added fluid and all was good. Well if that ends up the case could I swap both ways and have a supercharged monte and an NA bonneville to sell? Except for this deal on the engine Im trying to not put anything else used into my car. My budget is kinda low currently also. Monte has 196k miles on it but ive replaced just about everything non cosmetic with new parts. The NA 3800 currently in it has also had alot of work done on it. And to answer the question about what kind of work to do while its out, say I have 500 dollars dedicated to parts for increasing performance. Is there an improved cam I can get that that the stock engine can handle without replacing too much else?

 

Just keep in mind that you will have to re tune it either yourself, have a tuner do it, or get a canned pcm tune from a vendor mailed to you. The complexity will vary from a simple copy and paste to actual tuning depending how many other mods you do at the same time.

Does that ~200k miles include the engine? If so, I'd probably be inclined to swap the whole new engine in assuming it's significantly lower miles.

A cam is a good one to do while everything is out. You'll just want to match it to the ultimate plans for the car (I know you mention low budget here, but I also remember your other thread you were talking about a supercharged, AWD, LS swap - so if youre changing direction to a big 3800 build, that could impact which cam you choose as you wouldnt want to buy it twice).

If this is just for a basic 3800 build, you'd be looking at something like ZZP's VS or XP or Intense's S1X. With that said $500 might be a bit tight if you're serious about replacing it all with new. The cam alone is going to be nearly $400 with shipping. Depending which cam you picked and how much you replaced / upgraded (springs, retainers, lifters, timing chain, etc) you could get over $500 pretty quick.

Curious what all is done to it? You just don't really see many built up NA 3800s anymore.

 

Just stock items replaced with OEM parts new. Injectors, coil packs, and whatever was in the rebuild kit my mechanic had back then. Was a 500 dollar kit. Cant really remember aince it was last year and at the time i had no interest in doing anything but ensuring reliability. Also i found a 500 dollar 02 ss with a broken engine i havent diagnosed yet im saving for awd project and the ls4. Plans changed abit with finding that bonneville with the supercharger. Figure ill do what is proven to work first and then get on to my experiments.

 

Unfortunately you're going to lose all that stuff anyways then. The coil packs and injectors are different on the L67.

My bigger concern would be bottom end wear with 200k miles. If the new L67 is notably lower mileage and you have a good feel for the condition / history, then id probably just swap the whole thing.

 

Theyre almost identical in miles. Figure ill swap both around and make a second working vehicle to sell.

 

Makes sense.

IMO you're probably better off with a top swap then, at least you'll be 100% sure in the bottom ends history. Just keep in mind going that route, you'll need to do something to run the stock pulley knock free (that cam you were looking at, a few bolt ons, or have the tuner pull a few degrees of timing out for the short term).

It'll also let you freshen up the top end gaskets and inspect the blower (to see if it needs a coupler or bearings) while its apart.