Just thinking out loud here for a few minutes....

Picked up a Firebird Vin K L36 motor yesterday for $100. At the time I was mistaken about the difference in the cylinder heads (didn't know the Series II motors had a shorter block deck compared to an LN3 3800)

One thing that surprised me a few minutes ago, while putting it on an engine stand, was the position of the starter is on the wrong side for a normal RWD car...it'* on the driver'* side, which is the correct location for a FWD car (i.e., towards the front of the car to not interfere with the transaxle.)

So, I'm wondering if there is any difference between the 3800 series II block used in FWD applications vs. RWD applications...or did GM finally get smart and design a block that works in both applications?

I guess I'm wondering if I should hang on to this long block as a possible replacement for the '90 Bonneville should I succeed in grenading the LN3 with a supercharger. (Yeah, I would have to finish dessing it out with intake and exhaust manifolds and the correct timing cover to use it in a FWD application)

The block is the same but the accessories on the belt side are in different locations.
Some other things that are different are the harmonic balancer, intakes face the wrong way, and if your engine was hooked up to a manual then you'll need a different flywheel.
So basically you can use the heads, block, rotating assembly, timing cover?, and waterpump are the same for fwd.
But putting that engine in your 90 would be difficult. Especially if you don't have provisions for the torque axis mount on the passanger side. Then theres custom chip tuning or a complete obd2 swap which would mean you need a differnt tranny.
Don't get me wrong, you can definitely swap a fwd l36 into your 90 but it just depends how much work and $ your willing to do.

Still thinking out loud... Took the motor down to a bare long block over the past two hours. Yes, all I might be looking to use is the long block, then pick up all the FWD version odds and ends from the local junk yards (like intake and exhaust manifolds)

While junk yarding yesterday morning, I ran across a couple of mid 90'* Bonnies/Ultras that had the torque axis mount. I might snag one next weekend as they were pretty easy to locate and I do have the frame mounting holes in my 90 Bonneville for it. Did they use the same mount on all models? Just wondering if the brackets on the engine side are different for the SC model vs. the NA models (i.e. if I add it now will I have to remove it with the SC on the car (yes, I know it has to partially come out to get the serpentine belt on)

BTW, just an FYI for anyone who cares. The throttle body and the cable mounts do support the TV cable for a regular 4T60. I took the spare TB I had from a LN3 and once you remove the screw from the end of the shaft, the linkage for the TV cable comes right off and goes on the newer TB in the right location to operate the TV cable to the 4T60. In my case, the cable bracet from the M62 SC even had the cutout for the TV cable retainer/adjuster.

May not matter to y'all, but to me it means I don't need the 4T60E and it'* PCM That keeps these projects mostly mechanical in nature without delving into rewiring the car.

But how are you going to run an l36 on your pcm?

Using the LN3 sensors on it. When you get right down to it, both motors are the same displacement. How is the 90 ECM going to know any different? Yes, it may need a chip change to adjust the fuel and timing for more efficient heads, though maybe not.

Another pair of amusing hacks from this weekend:

MAF sensor from the LN3 fits the newer TB'* with the aid of a thick rubber gasket to seal the larger bore. (used a spare rubber washer from an LT1 Throttle Body TPS sensor)

Rubber duct from the LN3 will also fit the newer TB'*. I heated up the rubber in hot water to soften it up, and it has enough stretch to fit around the larger diameter TB inlet. Might pick up the newer airbox assembly at some point, but until then the SC can run attached to the LN3 airbox.

No worries here. This is a thinking out loud session.

Gear ratio: Hmm... would be nice to have a numericly higher ratio. Something to inquire about with tranny shops (can a 4T60 be assembled with a different ratio?) I'm curious too since everyone is telling me I'm going to grenade the tranny along with the motor.

Knock sensor...non-issue. The L36 wouldn't need the two it came with. Take the one off the LN3 and put a 1/4 pipe plug in the hole where the 2nd one was.

Funny memory came to mind. Back when the '87 Camaro was still powered by a 2.8L V6, I tried to kill it and it just would not die. I figured 75 shots of nitrous oxide should have killed it, but it still kept going, and going, and going... I wonder if the LN3 is going to be the same way... The more I try to kill it, the more stubborn it will be about dying

I'm not 100% on this but you'll have to use the harmonic balancer from your LN3 because I believe the key-way changed.
I'm curious to see how bad the fuel trims would be.
Are you going to get the FWD LIM/UIM?