The 8.1L was a great alternative to a Duramax. I bought mine brand new on September 21, 2001 during the “Keep America Rolling” campaign after 9-11. It is somewhat rare with a 6 speed manual and bucket seats (& 4:10 gears). Almost 13 years later and I’ve only racked up 61,000 miles on it. The truck is like brand new and bone stock inside and out, right down to the airbag decal hanging from the glove box. I love the engine but I absolutely hate the truck and the ZF 6 speed as it has the most awkward shift pattern and shift gates of any manual I’ve ever driven, hence the reason it has low miles (I drove an ’89 Suburban and ’92 4Runner everywhere else). It is also the worst riding truck I’ve ever owned. I’ve been very seriously considering selling it as I am beyond tired of the 6 speed manual and have a major man crush on the new 2014 Silverado 1500’s but we have fresh baby at home so it will be a while before a new truck will happen.
I also installed an 8.1L in my K10 in 2008. Works great and still better on fuel than any old carbureted engine ever could be with twice the power. It is like having diesel power without the BS of owing a diesel. This one is running Torque Management delete, EGR delete, drive-by-wire delete, a hot tune added and a bump in fuel pressure. The tuner claims to have dyno’d this combination at 425HP/555 lb. ft. of torque. It doesn’t take much to wake up one of these beasts. A larger cam would even do more wonders for it. I have one more 8.1L hanging on an engine stand to go in to my Burb as well.
The only reason GM discontinued the 8.1L is because they had to invest close to 100 million dollars into the Duramax to meet 2007 and 2010 diesel emissions. The 8.1L cannibalized sales from the Duramax in the medium duty and HD trucks and with the 8.1L needing another round of emissions certifications in 2010 as well (with a cost of around 6 million), GM chose to kill it off in hopes of forcing what would be 8.1L sales to a Duramax. Plus they had "bigger" plans for the Tonowanda, NY engine plant where the L18 was built. That is a fact that can be researched with googling.
BTW, the 8.1L is not dead. GM sold the production rights to an independent engine manufacturer where they still build it today for heavy truck manufacturers like Freightliner, stationary well pumps/generators, and the marine industry (Mercruiser, VolvoPenta, etc.). In fact, they have even hogged out a version of it to an 8.8L running on gasoline, propane and natural gas.
Here is a thread I created regarding all things L18 8.1L related. BTW, the L18 was never part of the “Piston slap” frenzy like the early Gen III small blocks. The piston design isn’t even remotely the same, although a very high mileage 8.1L can develop piston slap like any other old high mileage engine can. The L18 pistons are more common with the older L29 7.4L and all older big blocks, not the Gen III small blocks.
I snapped a few pictures of the last L18's to roll though the assembly plant for one of the vehicles my company built. This was in late 2010.
