Hey guys, i am looking into selling my current 5.3 P/U and getting an 3/4 ton Avalanche with the 8.1L V8. I have never had or even really looked into the big blocks before, so its new to me. Are you happy with the way they tow? any major problems or complaints? How about gas mileage? i know it depends on a lot of things, but just a general number on the highway. The main reason im looking into the 3/4 ton 8.1 is because i tow my car around a lot. my 1/2 ton does a pretty good job of it, but just looking for something different. Also, i put the comp 212/218 522/529 cam in my 5.3. are the ls1 style cams interchangeable in the big blocks? what about headers? I was thinking about taking off the headers/exhaust and cam if they can be swapped onto the avalanche. thanks for any info

Chad

 

no nothing is interchangable, you will probably get between 8-12 mpg. I would personally get a duramax quad cab for that price. the diesel will have alot more power, gas is cheaper, and you will get better mileage. probably somewhere around 17 on the highway.

 

my dad has one, it gets about 11mpg, but it'll tow anything. it pulled a 12,000lb boat like a play toy. it rides pretty nice too.

 

1 have one its about 14 on the HW and 11.7 ( according to the DIC ) for town/HW average, the motor is REALLY smooth, and it feels really nice on grades as it can accelerate up the hill with out shifting out of OD and i can just fly by everone else.

 

First what year is it? 04 have per-cats on them, just not many exhaust kits out there. If getting 8.1 get 4.10's. Also get it tuned and new air intake. These are the single most best improvements I think far as easy stuff to do. Then go cam and headers and exhaust. She'll have plenty of go power and be even more effient(mpg). But its pretty stout motor from the factory, but is very stuffed up(can't breathe). Far as the motor goes, dead nuts soild. nodular iron crank, forged rods, hypertonic piston(which can be a problem when spraying a 200 shot from what I hear) Plus raylar is coming out cool products for the 8.1, heads, cams, intake manifold, roller rockers, forged piston, forged cranks(I think). Not mention that comp cams has 3 cams for the 8.1, and Stainless works has long tubes for 01-03 8.1's. There lots of $tuff out there for them.

Over the past year all I have been doing is making breathing improvments. With the mods listed below in sig. I have been getting 13.8 to 14.5 combined hwy/city mpg. And getting 15.5 on the highway. all empty of course.

 

Thanks for the info guys, i appreciate it. I have tossed around the idea of going diesel powered, but i hate to say it...i would probably go with a ford diesel, and i really dont want to I love how the avalanche's look lifted, also. I found a really good deal on an 02 avalanche, so thats what i have been looking into. I guess that mileage isnt too terribly bad, my current 5.3 gets about 15-16 MPG on the highway but its lifted with 35" tires.
8100Hammer--what do you mean by per-cats on the 04's? performance or Pre cats? I would probably be going catless with a custom exhaust anyway, but was just curious. thanks

Chad

 

meaning two cats per-side(I think)