Who can tell me about big blocks?

[Pro_Marinero]

'm looking at an '01 Chevy 3/4 ton 4x4. It's a crew cab long box, but the box has been replaced with a custom tilt flatbed with a winch in the nose (about $6-8k worth of bonus). It's a NICE setup. My dad built a truck extremely similar to it except it's a 1/2 ton. Here's my dad's being used when we were loading sleds.

Here's the deal. It's got a gaspot 8.1L. If I had my druthers for a long-term rig I would go diesel. Obviously, mileage is the issue for me. I don't tow a lot right now and the big block is probably more than I need, but I feel like this is one of those trucks you just keep forever and put in a new motor when the time comes. The selling point for me is the bed setup. My dad built his bed for his '79 Ford 20 years ago and then when that finally bit the dust he swapped it over to the Chevy. The one I'm looking at is a factory-built setup.

Right now I've got a 91 Ford F150 4x4 with a 351. I was planning to just use it for a few years and then get a new one with a crew cab since we have two kids and one on the way. However, the F150 gets 12 mpg every tank no matter what. I don't think the big block is much worse, if any.

I'm looking for some input as to what others would do as I've never owned a big block. BTW... the truck has 130k miles and is going for $12k.

 

[Motley Doo]

Your milage is going to depend on the rear end ratio, pretty sure its a 4.11. Those BBC's are bulletproof! Thats a Gen VI big block, vortec heads, they make tons of torque, and you will probably put another 70k on her before looking at a rebuild(depending on how it was driven before!) I know guys that swear up and down that they get 14 mpg with the 8.1, don't know if its true, I think he has a Superchips tuner in it. The fact is that the 6.0 don't get alot more it any mpg, mine gets 12, but I drive it with my foot in the throttle! Fact of the matter is, good truck, great engine, good tranny in the 4L80E, and a deal like that, I'd jump on it! Big blocks, its worth the money to regularly change the oil and run a very good oil, Castrol Sythetic or it you can choke down the extra $20 a change, Amsoil! Good luck!

 

[moldy]

I agree, jump on it. You might complain a little about the gpm, but not about the power. And it sounds like you're driving something that doesn't do a lot better on mileage now. Doesn't the 8.1 come with the Allison? Not to knock the 4L80E but the Allison is a much better trans and would sweeten the deal even more.

 

[AKSNOWRIDER]

I've had two brand new suburbans..1 with the 6.0 and one with the 8.1...the 8.1 rocks...pulling a 4 place at 55 averaged 12-13 mpg...empty at 55 will pull 15-17.. now if your running 80+ loaded up hills...7-8 mpg...6.0 could match the economy but never bettered it....and was a mile a gallon worse loaded hauling butt...3.73 gears add about 2 mpg over 4.10's and as for the allison as much as I love that tranny I think it hurts fuel economy over the 4L80 E...good luck...

 

[catssuk]

we have an 01 8.1 liter with the allison auto 4x4 with over 300k trouble free miles on it, buy it. that truck should have the allison in it already, the moter and trans are basically bullit proof.

 

[Beels]

I've got an '01 2500 crew cab 8.1 / Ally 4X4 3.73 as well. It gets better mileage than my dad's '00 6.0L loaded or unloaded. I have 243,000 km (151,000 mi) on it now and it runs great. There's the usual GM Vortec issues like intake gaskets and oil cooler lines, but nothing major. It will also use a bit of oil as all big blocks tend to. Depending on how hard I drive it, it'll use a quart of oil per 2,000 miles.

 

[Dogmeat]

I just bought a 2005 Chevrolet 2500HD ECSB, 8.1L/Allison, 3.73's .... Only had 29,000 on it when I got it, I've put about 5,500 on it since November

I _REALLY_ like this truck. I like it WAY more than my old 1/2 ton.

Towing the exact same snowmobile trailer, I was getting 9 mpg with my 2000 5.3L .... I am getting 9 mpg towing the SAME trailer with this truck, however, it's not even funny how much better this truck pulls the trailer.

I bought this truck soley with towing ~6,000-lbs in mind, and for me it's perfect.

I think one day however I will put 4.27 gears in, because I put 285/75/16 tires on it, so that lowered the final drive ratio to what would be even lower than stock, which I don't really like the idea of ... I wish Iw ould have gotten the one with 4.10 gears but this one was in such good shape I didn't wanna pass it up.

Either way, it's still been lugging a 6,000-lb "large" 2-place enclosed snowmobil trailer up the mountains as well as I would ever want it to.

I am averaging about 10mpg around town, then at 75mph unloaded I'm getting 15 with it.

It's a gas hog yes, but I didn't buy it expecting good miledge, I bought it to tow with ...

And when you consider a diesel would have cost mr $4,000 at least more to buy then probably $0.40/gallon more to fill up, I'd say I did pretty well with this thing.

 

[Beels]

And when you consider a diesel would have cost mr $4,000 at least more to buy then probably $0.40/gallon more to fill up, I'd say I did pretty well with this thing.

That was my deal as well. I realize you still get the diesel premium at resale, but the operating costs just didn't make sense for me.

 

[Vern]

i'd jump on it, when i decide to upgrade that will probably be what i look for. my bros got an 03 2500HD reg cab with the 8.1/allison and its a great truck its got over 150,000 miles on it and still runs like a champ. empty he averages 12-13 mpg(driving civil) around town and on the one good long road trip we've taken it on it averaged 16 mpg with three dirtbikes in the bed and all our camping gear. i dont care what people say, it will do anything a diesel will and ive never seen any of the new diesels get any better fuel economy.

 

[Dogmeat]

I think you might get better fuel economy with a newer diesel pulling a trailer of the same weight as you with with the big block, but I don't really see how that's worth justifying the cost of however much more the diesel is to buy, then to insure, then to buy fuel for...

If I was gonna be towing a 10,000-lb trailer around regularly yeah I'd spring for a diesel, but I figure the truck I got, at least if I put the 4.27 gears in due to the tires I got, will be good for 8,000-lb any day .... I don't really ever intend on pulling more than that with it so it would have been patently stupid of me to buy a diesel just for the sake of having a diesel.

 

[Motley Doo]

Did all the 8.1's have the allisons behind them? I can't remember!

 

[Dogmeat]

Did all the 8.1's have the allisons behind them? I can't remember!

If you had a 2500HD or 3500 series truck with an automatic transmission, yes.

The only other transmission option was a 6-speed manual if I remember right.

If you bought a Suburban with the 8.1L in that, I believe the only transmission option was the 4-speed 4L80E ...

 

[Beels]

If you had a 2500HD or 3500 series truck with an automatic transmission, yes.

The only other transmission option was a 6-speed manual if I remember right.

If you bought a Suburban with the 8.1L in that, I believe the only transmission option was the 4-speed 4L80E ...

The 2500 Avalanche was the same way.

 

[Dogmeat]

This thread got me thinking ..

Do you guys think GM will ever offer a big block in their HD trucks again?

I know that as of 2007 you couldn't get the BBC in the new generation of GM trucks ..

They tuned up the 6.0L a little bit for these trucks, but it's still nowhere near as good of tow motor as the 8.1L is ...

I really wish you could still get a BBC in a new truck honestly, I figure before too much longer I'm gonna be needing a crew cab .... heh

 

[Motley Doo]

You can, can you say engine swap! GM High Performance has a 620 horse 572 that will light the tires up on any tow rig! Or if you want to mix a little race gas, you can step up another 100 hp! Something about a solid roller cam longer than 270 degrees of duration @ .050" lift. They need to offer THAT engine package! Ah, if only.