Thinking of upgrading from a 7.4 to a 8.1 Gasser

BenK wrote:
Smaller fuel tank on the GMT800/GMT900's

Actually the 8.1 burbs have a 26 gallon main tank, and a smaller 12 gal tank that sits above the spare tire, so 38 gals total fuel capacity. Both tanks have their own in-tank electric pumps, fuel sending units, and fuel/return/evap line sets. The fuel filler neck goes into the smaller rear tank, and there is also a 2" filler hose that allows fuel to flow from the higher rear tank into the lower front tank.

When running the front main pump is primary, and the PCM turns the rear pump on/off according to some mysterious algorithm. The PCM averages readings from both fuel senders to come up with a general level to display on the dash gauge.

I became quite informed about all this when I replaced the rusted fuel lines with stainless this spring. A complex set up for sure.

The fuel filter is easily accessible on the inside of the frame rail under the drivers door, but is right in front of the ABS unit so a little cramped to get to.

And good point on the hitch receiver too, should be replaced.

We had an 04 sub sit at the dealership for less than a month. 8.1 fully loaded sub w less than 100k sell for 16k.....

For what's it's worth. I just sold my 1999 454 Burb and now have a 2005 2500HD with the 6.0. It doesn't have the grunt of the line that the 454 had, but a major difference at highway speed. Better mpg too. 8.1's are hard to find in the trucks but more common (it seems) in the Burbs.
So far I'm not regretting getting the 6.0.

Most people with 8.1's will be burried with them !

Add that the spare tire is removed from the inside (GMT400) and now where the
GMT400's 42 gallon fuel tank was. That does increase the interior cargo room
considerably

Smaller fuel tank on the GMT800/GMT900's

Very poor designed receiver on the GMT800, if you get a GMT800 replace it not
already by the previous to a traditional designed. GMT900 receiver is limited
to 1,000 lbs MAX in WD mode

Ok, dimensional POV it is stroked not bored, but point is that the whole design is different, new heads, new cam, new intake, new block, etc.

2003 was a mid-model-run update, and the burb got things like digital OnStar, steering wheel audio controls, and a few other perks. I know the crank position sensor design as updated, but basic motor and accessories was the same.

Correct on oil/trans lines leaking, forgot to mention that. I've not had a problem getting parts overall, with some exceptions like straps for the rear fuel tank and one or two other items. Nothing major.

zell66 wrote:
Ok first off I DON'T WANT TO BE TOLD DIESEL IS BETTER!!

I do not drive TV enough to justify a diesel, My current TV is a 196 GMC K2500 Suburban and in the last 3 years I have put on 6,000 miles. I am thinking of upgrading to a 2001 GMC Yukon XL with a 8.1.

My old girl is getting tired and I am towing at the upper end of its capacity, The Yukon has a 12K towing capacity and 177,000 miles.

What things should I be on the lookout for?? There is some rust on rear door quarter panels but overall not bad.

.............I'd move up to a 2003 , my Chevy has all filters accessiable , esp. fuel filter on inside frame rail , takes 5 minutes to change . Oil cooler lines leak as well as tranny cooler lines so be sure and check those when evaluating a truck for purchase ! I've read some parts on 2001 are hard to find , and GM made various improvements in 2002 and 2003 and later years . , jf

BurbMan wrote:
Why I am never selling mine! Something about big CID rumble vs turbo whine....

10 mpg is pretty much the norm, can baby up to 12 or 13 on the hiway at 55 with the cruise on. Towing at 65-70 usually gets me in the 7-8 range.

When the 8.1 was introduced in 2001, many thought the 496 was just a bored our version of the 454, but GM says complete motor was redesigned and shares few/no parts with the old 454.

But direct injection and other technologies we see on the eco-boost designs will make the 8.1 obsolete, just like the 8.1 made the 454 obsolete...*sigh*

For a dimension point of view, it is a stroked version of the 454, not bored. It doesn't share parts because the 8.1 uses metric hardware.

Why I am never selling mine! Something about big CID rumble vs turbo whine....

10 mpg is pretty much the norm, can baby up to 12 or 13 on the hiway at 55 with the cruise on. Towing at 65-70 usually gets me in the 7-8 range.

When the 8.1 was introduced in 2001, many thought the 496 was just a bored our version of the 454, but GM says complete motor was redesigned and shares few/no parts with the old 454.

But direct injection and other technologies we see on the eco-boost designs will make the 8.1 obsolete, just like the 8.1 made the 454 obsolete...*sigh*

Had a 33' Class A with an 8.1 coupled to the 4L85 (2006). I'm a big Ford fan but I did like that 8.1. Pulled that motor home with toad very nicely.

I've driven several 454s and my 8.1 service truck at work will run circles around any of the later 454s but what a gashog... OMG! I think the 8.1 even has more suds than the first high compression 454s. Craig