8.1L swap into my 7.4L K2500 Burb

[someotherguy]

I kept looking at LS swaps for my old '94 and eventually it led to just buying a truck that came with an LQ9 from the factory.

Richard

 

[90halfton]

If I was going to spend any kind of time, money, and fabrication on a swap on a 3/4 ton it would be a 12v Cummins. Big torque and great mpg. And no shortage of parts and support. And you can get one comparably priced to a modded big block/ fi system.

 

[4Birdman]

I noticed that the 454 guys are all chiming in as 454. Have you considered the 6.0?

Nah, that's not going to happen. I've had a few 6.0L trucks and a few 454 trucks and the BBC trucks would out tow my 6.0L 2500s any day of the week. I mean, a stock 454 has 70ftlb more than a stock LQ9.

I think I'll stick with the Vortec 454 with the FITech setup. I don't mind the wiring or anything, but the availability of parts is something I don't want to deal with. This truck will be towing my race car long distances so if I break down somewhere I don't want to be SOL at finding parts.

 

[Jay33089]

Nah, that's not going to happen. I've had a few 6.0L trucks and a few 454 trucks and the BBC trucks would out tow my 6.0L 2500s any day of the week. I mean, a stock 454 has 70ftlb more than a stock LQ9.

I think I'll stick with the Vortec 454 with the FITech setup. I don't mind the wiring or anything, but the availability of parts is something I don't want to deal with. This truck will be towing my race car long distances so if I break down somewhere I don't want to be SOL at finding parts.

To each his own . I love mine but that's me. Parts availability wouldn't be an issue I would think, as many 6.0 2500s as theyre are out there. Every piece of my swap was either off a 800 or a 400. Just as matter of knowing which is which!

 

[4Birdman]

I've got LS parts coming out my ears here in my shop. I have a built LQ9 in my Trans Am. I just prefer the low end of the BBC.

 

[Supercharged111]

Man, lots of 8.1 haters in here. I'd do the 8.1 hands down if you can get it cheap.

 

[someotherguy]

Hmm, I didn't see any of the typical 8.1 hate at all in this thread, just some facts. The 8.1 is harder to find parts for than a 7.4, especially if you're talking about performance parts. It will definitely be a bigger job to transplant an 8.1 from a GMT800 into a TBI-era GMT400, vs. transplanting a GMT400 Vortec 7.4.

That 8.1 swapped in there with a good tune to remove most of the torque management, would be a monster. No doubt. But it's no small job, either!

Richard

 

[Supercharged111]

Be that as it may, what kind of parts would really be needed? They're pretty bulletproof from what I've seen. 454 exhaust bolts right up I do believe, only variable is taller deck. If he's down for the wiring I don't see a reason not to. Yes more work, but I wouldn't think a ton more? I'd love a blown 8.1 but the cost of getting the engine has been really off-putting for me.

 

[Tom P]

Man, lots of 8.1 haters in here. I'd do the 8.1 hands down if you can get it cheap.

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.

 

[Supercharged111]

He wasn't asking if it was cheaper or easier. OP of you get the whole truck it'll either have an Allison automatic or 6 speed MANual, I'd rock either before the 4500. If not, they do bring money.