Got the itch to build a motor to replace the 8.1l in my 01 Yukon 2500. I tow a boat that weighs in around 7500lb around AZ (sometimes socal) in the summer, so lots of heat and long grades to pull. Truck is 4wd with 3.73 gears. Truck has sentimental value, so not looking to replace it with a diesel. Im thinking something in the low-mid 400s hp/tq to the rear wheels should be enough based on my experience towing this boat with many other trucks (Silvy SS, Tundra 5.7, etc) and shouldn't need to do anything special to the 4L80e.

What would you build? Block, heads, cam, intake, etc. I would love to go FI, but serious heat concerns there, but willing to listen to someone whose gone that route and pulls in similar conditions. Also willing to hear about what you would do to the 8.1, or a complete new build. Budget is 5k, and looking for reliability above all - don't want to deal with something temperamental that leaves us stranded.

 

If it were me, I would 6.0 that thing with a blower.

 

Find a low mileage complete 6.0 gasser, add a cam for a supercharger, upgrade heads (valve springs, push rods), put headers and exhaust on it, and whipple it. Going to be about 8K though.

 

Going from 8.1 to 6.0 is a terrible idea.

 

Definitely is not. the 6.0 does everything the 8.1 does, except aftermarket is both A) available and B) affordable.

Put together a list of parts needed to take either to 500/500, and get back to me.

Start shopping:
Vortec 8100 8.1L Chevy GM Performance Parts - GEN 7 Big Block - 496MAG HO Marine Performance Parts - Raylar Engineering

 

Exactly. Im sure the Rylar stuff is great, but his market is guys with 200k offshore boats rocking 2 8.1s, not dudes with 5k$ SUVs.

 

Keep the 8.1L, Ditch the 4L80E and go to an Alisson. The 8.1L is de-rated in the Yukon chassis because of the 4L80E. The same exact engine in a truck with an allison has a higher rating even though the Engine code is the same.

Without spending Big money, About all you can do is a cam and springs with tuning. There is some small DIY mods you can do like opening the intake and so on but not a whole lot else. The Dart heads are better than stock but are they really worth the money for what you get?

The 8.1L is a beast. We kept up with Diesel's in my buddies 8.1L truck towing about 8K.

 

Check out raylar engineering, they are all into 8.1's, why not leave the 4l80 if it works fine and add a deeper pan along with a big cooler. If it gives you problems then at that time look into a better trans rebuild or replacement. Could also do a lower gear in the axles to help some.

Vortec 8100 8.1L Chevy GM Performance Parts - 496cid BBC Truck / SUV Performance Packages - Raylar Engineering

 

Simple.

The Allison is a 6spd trans. It's first gear is almost equivalent to the 60e with a ratio of 3.49:1 (depends on which model Allison it is).