6.0 vs 8.1 swap in G30 motorhome

Figuring out my budget - so any input you have is highly appreciated.

So I'm going to do a swap, this I'm convinced of. Putting another low performance 350 in my baby (22' Class C Lazy Daze) is not an option. Doing 40mph up a 6-7% grade sucks worse than you can imagine.

The only question is... big block or small block?

The 6.0 looks pretty easy to drop wire and fire but one of my buddies suggested I look at the L18.
My rig already has a 4L80E so the only real headaches I have to deal with are motor related.

Any pros/cons of one vs the other? If I go with the 6.0 the only mod I really want to do is a cam and maybe headers, the closer to stock I can stay the better.

I know the 8.1 smashes the 6.0 in terms of torque but I am not aware of fitment issues, fuel economy, etc (I would think the LQ4 would be better but hauling such a heavy load all the time who knows). I know for sure the TBI 454 fits because that was an available option for my rig, but I don't know how that translates to the Gen VII motor.

Thanks!

I hope this isnt taboo or frowned upon here, but what about a 6.5TD?

6.0 all the way unless you have the dough for a duramax. 6.5TD is not a step forward.

It's a motorhome, needs torque. 8.1 The 6.0 would have to work that much harder so it would pretty much eat up the fuel mileage difference. Why not a Cummins? And old 6bt should be an easy swap

I'd do a Cummins before I did an 8.1. Chevy dropped it for a reason.

Well if diesel is a option I would definitely go with the duramax better mileage and torque out the wazu, but if your going to stay gasoline I would go with 8.1 don.t think your going to see a big difference with the 6.0. Motor, but if your really going to make a big change Duramax all the way, better mileage and lots of power, which would make more since in the long run considering gas is going back up.

If diesel was an option I'd seriously consider it.

However this swap needs to be emissions legal (at least be able to pass a tailpipe sniffer).

I'm not thinking you would have any emission issues

Quote:

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Originally Posted by zeake

I'd do a Cummins before I did an 8.1. Chevy dropped it for a reason.

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what he said. The cummins is an amazing motor and you can pick up the 12 valve ones pretty cheap and they'll go 500k miles no problem.

Quote:

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Originally Posted by collin

what he said. The cummins is an amazing motor and you can pick up the 12 valve ones pretty cheap and they'll go 500k miles no problem.

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And most likely pass emissions. Most diesel forums can answer the emissions questions. Plus it is leagl to upgrade to newer model engines you just have to retain all emission stuff from that year model engine. I know that will get you pass a sniffer.

K, but does the cummins hook up to the 4L80E if not you would have to do a tranny swap also. Just thinking if you did a duramax it would be easier and don't care for that old cummins stuff anyhow, if you go diesel its going to cost craps loads, why not go for the best.

Because Duramax isn't the best. Look at the worlds fastest/most powerful diesels... They're Cummins. Don't get me wrong, the D-Max is nice and is coming along, but it still doesn't surpas the old Cummins 12v.

Every cummins in my town blow black smoke for a mile, and couldn't pass a 4 cylinder if they tryed. That image has run't it for the cummins for me. My moms escort could smoke them. Fast is not what diesel is meant for, rather for hauling heavy loads with fuel mileage gains. So if you want both go diesel, if you just won't power the 8.1 will do it. I'm not going to fight the diesel powerplant issue, in the real world we just call them diesel dummys and they'll fight you till your blue in the face, fast thay are not, but they do have benefits in your purpose.

Do you even read what you type before you post it? He isn't trying to make his tank of a vehicle fast. He's needing something with TQ that can pull a brick shithouse. The 12v Cummins is one of the best around for that. 10x better than the worthless 8.1

Quote:

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Originally Posted by zeake

And most likely pass emissions. Most diesel forums can answer the emissions questions. Plus it is leagl to upgrade to newer model engines you just have to retain all emission stuff from that year model engine. I know that will get you pass a sniffer.

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depends on the state. I know here in CA you can't turn a gas into a diesel and expect to pass smog:(

Thanks for your input so far.

I cannot do a diesel swap - not possible. Washington state will not allow you to take an emissions controlled vehicle with a gas engine and swap to diesel. Even if I could a 12v 6BT Cummins would be really hard to fit underneath a G-van. The 4BT would fit better but they are super coarse motors (loud and lots of vibration).

So that being said (unfortunately) :( - which gasser would you think works better?

o sweet ur in washington, i live over near seattle, but as far as motors i would go with the 8.1 i know people dont like it but i drove a suburban with one with a mild cam in it, and it was able to drift and keep up with v6 mustangs. i know v6 but its a suburban.

So I'm building a list of pros/cons for each motor

Pro 6.0

Relatively inexpensive
Easy to find
Decent amount of bolt on mods and aftermarket support for swaps
Better mileage (in theory)
No issues with fitment
Done a million times in trucks

Con 6.0:

Need expensive bracket or compressor to keep AC
Piston slap issues? (dunno if this is really a problem, it's hearsay mostly)

Pro 8.1

TORQUE
old motor mounts work
TORQUE :)

Con 8.1:

Unknown fit in G-van (I know you need to notch the frame to fit into OBS)
Big and Heavy
Not much aftermarket support
Probably have to DIY wiring harness
Big Block fuel consumption

So that's what I've got for now - anything I'm missing?

I think even a 6.0 would be a ton better than a tbi 350, I know my tbi 350 was a whopping 190 hp stock.

IMO, 6.0 bored & stroked to 408. that should put u on par with big block torque while maintaining somewhat reasonable mpg.