Preparation for heads, uim, camshaft and downpipe

[IsaacHayes]

Check 3400-modified's threads for info on that. He swapped heads but I think he ended up modifying the coolant sensor to fit the head of the 3500 lol. I've heard of others taping the coolant neck to put the sensor there too. I'm not sure on the details but yeah it's different.

[gectek]

well themanifold vacuum ports are ontheUIM soyou dont have to worry about anything as long as u use the 3400 upper intake...the only thing i know that u have to do is to tap a hole for the coolant temp sensor, unless you can extend ur harness...is that right isaac...and that is it

[IsaacHayes]

The "UIM" or "plenum" unbolts and lifts off thats how you get to the injectors and the other bolts for the LIM.

You will need LIM gasket for the 3500 not the 3400.

For the other 3500 plenum issues see my thread here. Not all will apply to your car like the vacuum for transmission (yours doesn't need it). Nor will the stuff about the lower intake. But MAP sensor and vacuum for FPR etc little things apply.

[skinrock]

Well, from what I understand, the gasket kit that I'm ordering is for the 3500...so it should work I assume:

http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=12594816

[gectek]

yah the 3400 upper manifold will bolt right to the 3500 lower, andu can use everything else u have to make it work. just make sure the lower intake gaskets u use will fit the LIMport, and that the uppergasket is not in the way whenu put it on,u can cut a little off to fit. thats it

[skinrock]

Oh, so the plenum actually bolts into the LIM? I thought it was part of it...

If the 3400 "plenum" bolts onto the 3500, I'll just do that for now. I eventually want to get the 65 mm TB, and then I guess I'll get the adapter then...but I'm tight on cash till next week, and after that, I probably won't be able to get parts in time for the week of 4th of July, when I'm on vacation.

Anyways, you also said "the above mod and other little things". Is that in reference to using the adapter plate, or do you mean little things in general with the entire swap?

I was kinda under the impression that as long as I had the heads, LIM, head bolts (have), and gasket kit (ordering tomorrow), and some silicon, I'd have everything I need.

I only have one weekend, one shot at this...it's gotta go right, lol. I mean I have another ride available if necessary, but I don't wanna go there...

[IsaacHayes]

lol, well at least you figured out how to see it. I'll edit it to www.

Well if you use the 3500 TB adapter, it doesn't have a square notch for the IAC flow. The older 3100 small ports didn't either but later the 3400 plenums had a notch so they changed the TB. I don't know why they changed.

But yes cut it like shown if yours isn't open. My small port 3100 52mm TB was open and would work, but the 3400 one I had required the modification. Once modified it will work fine on a stock 3400 plenum too so it doesn't make anything non-reversible.

If you use a 3400 plenum, no modifications needed. If you use the 3500 plenum then you need the TB adapter and the above mod among other little things. The 3500 plenum is a better design than the 3400 one. But if you don't want to mess with that stuff then a 3400 plenum will bolt to the 3500 lower just fine.

[skinrock]

well I gotta admin, the pic is a little confusing, are you saying it's gonna maybe take some custom work to use the stock TB, since I have to use a 3500 adapter with my LIM?

[skinrock]

Yeah and if using the 3400 TB on the 3500 with adapter this is how you do it:

had it edit the link, I'm logged in on www.60degreev6.com, which doesn't carry over to just 60degreev6.com, lol.

[IsaacHayes]

Yeah and if using the 3400 TB on the 3500 with adapter this is how you do it:

[gectek]

if you are using the 3500 UIM then u will need the adapter plate because it has a different patten. the 3500 TB was drive by wire, so there was no cable on it. they sell the plates on the store here for that

but if you are using the 3400 UIM, then u wont need it

[skinrock]

Hey, I was just reading another 3500 swap thread, and there was mention of needing to change the adapter plate for the throttle body. No one mentioned this to me, is this necessary?

My project still consists of swapping in the 3500 heads and LIM.

edit: I guess Isaac mentioned it, but it got lost in the midst of the conversation.

[whitelightnin04MC]

If I ever go to dynotech, I'll be sure to get something like the 3.29's or 3.69's.

[gectek]

those cars would def wake up with some better gears

[whitelightnin04MC]

Yeah, that's it. I get that last number flipped around all the time.