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Is the LG8/3.1 engine any better than the LA1/3.4 GM engine

GT2000

GT2000

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I'm wondering if the 3.1 engine is any better than the 3.4 by GM. A 2002 Montana has blown engine 3.4L and i would like to replace it. I know the 3.4 is notorious for head gasket issues. Does the 3.1 have the same problems? If they are any better, how much would I have to change around to put it in there. I'd love to cram a 3.8 in there but I doubt that would fit. If possible I don't want to put another 3.4 and have the same think go wrong again in a couple years. Let me know if anyone has a better idea. Is this a good idea, or am I getting my hopes to high. :th_mechanic:
 


Scottydoggs said:
id work on installing a 3800. hell you can even install super charged l67. its been done.
Click to expand...
Well how hard would it be, i really dont want to change much else but the engine. How much else would i have to switch around in order to make this happen
 
So you think it would be better to look in to the 3.8 instead of 3.1? I know they have more power but she wants something to drive not to race, or would you still go 3800 anyway
 
the 3800 is a better engine, but after reading that first post again it seems he did a fair amount of harness work to it. would be your call if you wanted to dig that deep. it could be a n/a engine too, dont need to be sc.

putting back in whats coming out would be the easiest plan in the end.
 


i dont think highly of either of them. both have major problems. and not sure if one is a direct swap or not for the other.
 
Ok thanks for the tips going to have to look into it a bit and figure what were going to do about it thanks
 
Probably too late to be helpful, but I don't think the 3.1 and 3.4 are much different. I'm pretty sure that the head gasket issues are nearly as probable in either motor.

If done correctly, with quality gaskets, you should only have to do the head gaskets on the LA1 once.

If you're still considering a swap at some point, I think the LX9 needs minimal modification to drop in. Good for 30 more HP and better gas mileage. It's basically an evolution of the LA1 and supposedly the head gasket issue was corrected. The main considerations are you have to buy/install and external crank trigger and decide what you want to do about a throttle body (LX9 is drive-by-wire, you need a cable driven option. Re-using your 3400 plenum and throttle body is an option.) Milzy motorsports has an article about it. Mostly a pitch for their swap kit, but the information may be helpful.

I love the 3800, but I think it'd be a lot more involved.
 


I thought the 3400 was just a bored out version of the 3100 with better heads? The lower intake shouldn't be an issue with the upgraded gaskets though. For the 3800, from the research I've done, you need everything from the subframe up. The top engine mounts fit right in, the axles from the 3800 fit the Montana, you'll have to keep the power steering rack from the Montana, if it's the older model I think all you need to do is splice the wiring harness at the fuse block from a gp, if it's the newer then you'll need to splice at the pcm and use a park avenue pcm, custom power steering lines, splice fuel lines, coolant hose should work from gp, heater core lines from gp should work, custom ac lines. If it has the 4T65E stock, keep it, while it's possible to modify swap for 4T60E,just don't. That's it. Stock tune works fine. You can get all wiring schematics from auto zone website, but let me know if you need help!
 
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