3.4 DOHC swap question

[95cutlassproject]

Greetings all,
Recently it came to my attention with my car that it is starting to get up there in miles (180k), and with my current classes in college i have been tearing down engines and pulling them out of cars which got me wondering. How much effort, or what in total would be involved in swapping out the 3100 for a 3.4 DOHC assuming i can find one. I do have the ability to tune my PCM and was wonder if that would make the swap any easier. (I had a love for this engine since i test drove one when my parents and i were shopping for a car and i have wanted to attempt this for 6 years now). This is my 95 we are talking about
Thank you in advance.

[robertisaar]

people swap out 3.4s for 3x00s all the time, can't be that difficult to do the reverse since it was a factory option at least.

[95cutlassproject]

What about PCM use. While at least today,while at class, someone told me did the 3.4 to 3x00 swap with the stock computer and it ran. (not well apparently)

[robertisaar]

since you're running a 95, when you find the donor 3.4 car, grab the C100 underhood harness as well and you'll be able to literally plug in all electrical stuff.

assuming you grab from a 94-95 car anyway. if you get a 91-93, there will be at least some changes.

and it depends on what PCM you want to use as well(91-93 94-95, 96 or 97).

[95cutlassproject]

So grabbing the C100 harness would allow me to run it off the current PCM in the 95. To bad the two local junkyards already scrapped the 3.4's that were in the yard.

[robertisaar]

if you want to run off of the current PCM, by all means keep your current harness.

basically, find out what PCM you want to run, and use the harness that would have connected to it. otherwise, you'll be crimping/soldering about 70 wires to change the PCM connectors. 91-95 all used the same shape of connectors(4 22 pin connectors). 91-93 share a common pinout and are speed-density ($DF mask). 94-95 used a different PCM and were MAF ($2E mask). 96 and 97 share a common connector setup (i think?) of 2 80 pin connectors, but were different in both years.

your 3100 harness has the 3100 specific connectors(and 94-97 LT1 as well, but IIRC, that's it), which are 3 32 pin pieces.

if you use the 3100 harness, you'll probably have to extend a few sensor wires, splice a couple of others, but it won't be the ~70 pin marathon of wires next to the PCM.

[95cutlassproject]

What would you suggestion be for an easy swap? Also what would be the best way to find one of these, i have been searching and can not find a decent deal on a running engine, the bone yard wanted 450$ which was steal compared to the 670 on ebay.

[robertisaar]

absolute easiest swap:

find a 94-95 LQ1/4T60E and it's C100 harness/PCM.

you would literally be able to plug everything in and go.

[robertisaar]

also, i got lucky and found someone about 75 miles away that didn't want their 95 LQ1/4T60E anymore and picked it up for $100.

however, assuming you don't come across that kind of deal, check car-part.com.

[95cutlassproject]

Oh my, what is this magic! where has this website been all my life!
!

[95cutlassproject]

How much more would be involved in swapping in an lx9 instead? I believe just some bolts need widening, plus the crank trigger, swapping the fuel rail.