8.1L swap into my 7.4L K2500 Burb

[dave_erald]

Towing all the time the fuel savings on a 6.0 would be the way to go. And there will always be parts on shelves if you break something.

The 8.1 wouldn't be a terrible swap, but parts availability might be a bit more of a problem I bet. It wasn't made for very long.

I would do the 454, fuel injection, aluminum heads and intake, match the cam and torque converter with the right set of gears and tire size to get your truck in the right speed and rpm for the cam and intake and towing down the road...I guess what I'm getting at is lay it out on paper what you're doing with it and at what speed with what tire. You'll be much happier in the end if you put a little bit of thought into things like that now

That's just my two cents

..oh, and grab a five or six speed stick if you were planning on going manual. More work you have to do, but more gears and more fuel savings is a handsome idea
EDIT - just read you are doing a nv4500 swap...so half of what I said is still good

 

[Sparkysikes]

Small turbo on the 6.0 that'd be great

 

[Whittaker]

with roller cam, the Vortec heads and multiport efi. Is such a better set up.

That said a great Mark IV block and a retro hydraulic roller and a set of large oval port heads then add a multipoint injection or FiTech or Sniper EFI on a 4 barrel intake and add a grand national fuel pump intank for the added pressure. So much more torque. Headers and exhaust of course. But added cooling will be needed also. Your looking at 500 ftlbs with maybe a 9:1 compression ratio from a pretty mild 454.

I have a 6.0 LQ9 in my Escalade and had one before in a earlier model. MPG is never more than 12.0 mpg. Ever.

My 95 1/2 ton has a built 406 and the TBI sucks and is a waste of time and money to mess with.

 

[Christian Steffen]

No 8.1 Hate here, but given the circumstances, parts availability, and desired outcome, I think a vortec 7.4 would be the cheaper, easier, better bet. I'd love to get my hands on an 800 w/ 8.1L but around here they are usually either lifted and beat to ****, or have a pile of miles and they still want duramax money for them. A naturally aspirated L29 496 stroker with a good cam will give you plenty of torque for towing, and with a stand alone fuel system, you could easily add fuel to compensate. I believe the original vortec fuel system is only good up to around 300 hp before bigger injectors and tuning is required. Christian Steffen has that exact setup in his truck... I'm surprised he hasn't chimed in.

I've got a mostly stock L29 in my truck with a 4L80e and 170K miles, but I have an exhaust and a "light" tune. I've towed all kinds of stuff and it doesn't seem to bat an eye. I'm not passing diesels, but If I want to haul a 4 ton mini excavator or a loader backhoe, I don't hesitate to do it.

I guess I'm just late to the party, I enjoy conversations like this. If the 8.1 is cheap and you are willing to get it tuned that would be an awesome setup, it should pull really well, but it may take more work.

The 7.4 with FITech would work well too. If you went that route, you could throw on an aftermarket dual plane intake pretty easily. A head swap would also be awesome but that starts to get pretty expensive.

If you run the stock intake, a 0411 swap with the 7.4 would also be pretty easy and should get the job done. Maybe I missed it in the thread, do you have a power/torque goal in mind?

 

[thz71]

Also late to the party but don't do the 8.1 I had one in my C3500 with the 80e. Like mentioned, there are parts that are NLA so that makes repairs crazy expensive. It gets TERRIBLE! Fuel milage. 6.0 swap is hands down the way to go. I've had 4 6.0 trucks and they're all around better. Easy and cheap to turn up and make more power than an 8.1 and better economy.

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[Christian Steffen]

Also late to the party but don't do the 8.1 I had one in my C3500 with the 80e. Like mentioned, there are parts that are NLA so that makes repairs crazy expensive. It gets TERRIBLE! Fuel milage. 6.0 swap is hands down the way to go. I've had 4 6.0 trucks and they're all around better. Easy and cheap to turn up and make more power than an 8.1 and better economy.

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The mileage and parts availability doesn't surprise me, I am curious about the power comment though. So a tuned 6.0 will produce more power and torque than a stock 8.1 or a tuned 8.1?

 

[thz71]

The mileage and parts availability doesn't surprise me, I am curious about the power comment though. So a tuned 6.0 will produce more power and torque than a stock 8.1 or a tuned 8.1?

Cam exhaust tune 6.0 yes will out preformed a 8.1 any day.

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[Christian Steffen]

Cam exhaust tune 6.0 yes will out preformed a 8.1 any day.

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You're saying out perform a stock 8.1 though, correct?

Dollar for dollar, I don't doubt that the 6.0 can out perform the 8.1. I'm just wondering what would win if you match the mods, so cam/exhaust/tune 6.0 vs cam/exhaust/tune 8.1. I'm really just curious, not arguing your experience here.

 

[thz71]

You're saying out perform a stock 8.1 though, correct?

Dollar for dollar, I don't doubt that the 6.0 can out perform the 8.1. I'm just wondering what would win if you match the mods, so cam/exhaust/tune 6.0 vs cam/exhaust/tune 8.1. I'm really just curious, not arguing your experience here.

Of course. But I would never try to make the dollar for dollar argument for an 8.1 against an ls engine. Have you looked up performance parts for the 8.1? For one they'res only like one company that supports them. For 2 even if you can find any the prices are insane. Ls parts are literally on every website and are dirt cheap. There's a reason you see thousands of ls swaps and maybe 5 8.1 swaps

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[Christian Steffen]

Of course. But I would never try to make the dollar for dollar argument for an 8.1 against an ls engine. Have you looked up performance parts for the 8.1? For one they'res only like one company that supports them. For 2 even if you can find any the prices are insane. Ls parts are literally on every website and are dirt cheap. There's a reason you see thousands of ls swaps and maybe 5 8.1 swaps

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Right, I know that 8.1 parts are extremely expensive. When the prices are considered, it is pretty hard to argue the 6.0. I was just asking for conversations sake, an "If money wasn't a consideration, what would you build?" question.