3400 topend on 94 3100

[achievasc92]

I recently picked up a 3400 LIM/UIM/TB for $26 off ebay. I know to use my current 3100 (non roller) heads I'll need to grind part of the LIM. And I know I'll need to buy/make an EGR adapter since I have to pass emissions. Other than that, I'm looking for some 00+ 3100 heads or 3400 heads, but if I can't find any that are reasonablely priced, what else will I need? I can't just buy roller rockers for my heads since they aren't notched right?

just one more question, since the 3100 Alternator has 2 braces that connect it to the PLenum how will I mount the alternator with the new 3400 plenum?

Thanks.

[bszopi]

just one more question, since the 3100 Alternator has 2 braces that connect it to the PLenum how will I mount the alternator with the new 3400 plenum?

Only use one brace. That's what I did and I haven't had any problems.

[achievasc92]

Nice, thanks. One more, I can use the UIM/LIM bolts from my 3100 with the new intake right? because the one I bought didn't come with any bolts.

[bszopi]

Yeah, they will work just fine. I would recommend getting the newest gasket kit from GM, as well as reading the TSB about proper tightening sequence. Its around the forums somewhere...

[bszopi]

So you don't have to search...

http://www.60degreev6.com/index.php?name=PNphpBB2&file=viewtopic&t=1993&highlight=lower+manifold+tsb

I need to add that to the 3x00 maintenance section one of these days...

[achievasc92]

another question:

I've been searching all over to find a good picture of the EGR adapter plate I need, (top mount digital/ sidemount newer valve) I know how to adapt the actual valve to the side mount on the plenum, but what I can't figure out or find a picture of is where and how the EGR tube connects to the adapter. If anyone has a few good pictures of the adapter I'd be much obliged.

[geoffinbc]

You mean how the stock tube goes into the stock adaptor (the plate between the valve and plenum) it is a press fit or shrink fit. I have never removed nor installed the actual tube. But it is in there tight.

[achievasc92]

On the 3100 the EGR tube inserts into the valve from the bottom, but on the 3400, even with the adapter, the valve will be mounted sideways, I'm just wondering how the EGR tube is mounted with the valve sitting sideways like that.

I guess I'll probably be better off buying one from someone else. lol

thanks though

[bobgagt]

I want to bring this thread back to life here... I got 3100 lim / uim from a 2000 malibu I'm going to use... is there anything that has to be done for these to fit the car? I have a 98 3100... I'm just wondering how hard this would be... I've already changed the lim gasket on three cars before so I'm familiar with that but is there anything else that needs to be done when changing to the newer style manifolds?

Thanks guys
-Bob

[TheDirtyBen]

if you have a 98, why put on a 2000? they are basically the same. the only exception is, they changed the way the EGR mounts to the UIM in 99. if you do the swap, you'll need a 2000+ EGR. i don't know if the connectors are the same or not. anyway, i don't see any performance benefit between the 98-2000 intakes.

[v6h.o.]

if you have a 98, why put on a 2000? they are basically the same. the only exception is, they changed the way the EGR mounts to the UIM in 99. if you do the swap, you'll need a 2000+ EGR. i don't know if the connectors are the same or not. anyway, i don't see any performance benefit between the 98-2000 intakes.

He has a 98 3100 engine. All 3100's up until the end of the 99 Model year all used what we call "small port" LIM and Plenums. they have a 12bolt upper plenum, where as all the 3400 Plenums/LIM's and from 2000+ on all 3100's are all the 6bolted Plenums which are refered to as "Large Port"

HUGE difference in port shapes/diameters, More to gain in Flow.

[v6h.o.]

I know i have pics of my own comparing side by side.. but i cant find them.

here is some exterior shots:
old 3100 style


large port style:






and now the even larger plenum less runner 3500 style:

[Quintin66]

Man, somebody's got one hell of a lot o' elbow grease in that setup!

[TheDirtyBen]

oh crap, that 3100 plenum looks like what my 94 achieva had. good thing i got a 2002 3100 then.

[Rhedalert]

Is it my eyes, or does dirtyben have the same avatar as Brad?