8.0L 496 gen 7 questions!

[90BCk5]

so I'm pondering a engine swap in the near future and i just came across an
8.0L 496 8100 vortec gen 7 casting #12556110. From what i read its a 4 bolt main and a cast crank, unfortunately it was from an industrial application (pumpjack driver) and would require a rebuild, and i would have to source a wiring harness. I am going to keep my eye out for a BB in a vehicle application to solve the wiring dilemma. I am wondering if anyone has had luck building decent power out of these units with cam and a tune like the 6.0?

 

[DEMON44]

Yes they work well. A guy I used to work with did that, and put it in his 67 ragtop firebird.

 

[454Sub]

I just built one with a cam, ported intake, headers, and roller rockers and all that other needed stuff. It is a 100% beast, with destroy any 6.0 that hasnt seriously been worked over, keeps up with tuned newer diesels no prob and now it averages 15mpg. Dont use a handheld tuner if you cam it, take it and have it dynoed and get it done right.

 

[90BCk5]

I just built one with a cam, ported intake, headers, and roller rockers and all that other needed stuff. It is a 100% beast, with destroy any 6.0 that hasnt seriously been worked over, keeps up with tuned newer diesels no prob and now it averages 15mpg. Dont use a handheld tuner if you cam it, take it and have it dynoed and get it done right.

Using stock bottom end? any links to your build?

 

[454Sub]

Well besides bearings and rings, we lightened the crank. Other than that, stock rotating assembly. This one was in a 2500hd though, not sure if it is a 100% same as your engine. Just a thought.

Search for "8.1L dyno test today". I'm fairly certain there is a list of parts I used. If not I can dig out the build sheet I have. Ended up with somethin like high 600s on torque and 4?? on hp. At the crank of course. Can't remember anymore, been awhile. Only problem we had is the fuel system still needs upgraded to handle it. But 10k miles so far so good.

 

[90BCk5]

Well besides bearings and rings, we lightened the crank. Other than that, stock rotating assembly. This one was in a 2500hd though, not sure if it is a 100% same as your engine. Just a thought.

for sure, thanks for the link, ive got a lot more reading to do before i get there any way. what year was the donor truck?

 

[454Sub]

04. Do yourself a favor and find an 03 for parts. The 04s fuel system is returnless, and the regulator is in the tank. Stoopid. The 03 has a regulator on the fuel rail (the 04 has the spot, no regulator), and its vacuum controlled, so much easier to adjust. I am in the process of converting the 04 I did to the 03s style.

 

[90BCk5]

What trans are you running behind that thing? TH400 or a 4L80e?

 

[454Sub]

Factory Allison. Im not sure you could even get one to run without some MAJOR electrical work with a th400. To be honest, Im not sure they came with a 80e either. Dont catch me lying, but I personally have never seen one. Basically, the 2500HD/3500HD with an 8.1L is a Duramax pickup minus the Duramax itself. So it has the 11.5in rearend, and all the other Duramax crap from what I have gathered. Where the 6.0 comes with the 4L80e instead of the Allison. The 6.0 might come with the 11.5in rear though, not to sure on that.

Only problem you will run into if you do the same basic stuff I did was the fuel system wont be able to take it stock. Im going to be putting in a Walbro 225 pump, and a 03 adjustable FP regulator and crank the pressure up to around 65 or so (stock is 58ish) and HOPE the injectors can take the extra flow.

 

[90BCk5]

The Allison would be a better deal anyway, I'll be looking for a whole donor truck, and I will definitely be following your build an keeping an eye on your fuel issues (or solutions). but thanks for the insight into the build, gives me a better idea.

 

[plyr2k]

Factory Allison. Im not sure you could even get one to run without some MAJOR electrical work with a th400. To be honest, Im not sure they came with a 80e either. Dont catch me lying, but I personally have never seen one. Basically, the 2500HD/3500HD with an 8.1L is a Duramax pickup minus the Duramax itself. So it has the 11.5in rearend, and all the other Duramax crap from what I have gathered. Where the 6.0 comes with the 4L80e instead of the Allison. The 6.0 might come with the 11.5in rear though, not to sure on that.

Only problem you will run into if you do the same basic stuff I did was the fuel system wont be able to take it stock. Im going to be putting in a Walbro 225 pump, and a 03 adjustable FP regulator and crank the pressure up to around 65 or so (stock is 58ish) and HOPE the injectors can take the extra flow.

2500 Avalanches and yukon xls with 8.1s came with 4l85e's and a 10.5" 14 bolt.