Installed the 3500 manifold

[gpse3400]

A few days ago I installed the 3500 upper manifold with a 4.3 70mm tb on my altered 3400, overall I'm pleased with it. Although my tuning went straight out the window as far as idling is concerned, response is exceptionally crisp. Cracking the throttle open 30% causes the tires to light up pretty good. Bottom end is definately improved beyond the seat of the pants feel. Its like a well built VIN W/T 2.8/3.1 but even better. As far as HP is concerned, operating range is still the same, up shifting at 7000 as before. There is more power to be sure. Overall the production doesn't seem to have that ramping exponential effect that the older manifold used to have. The power is just very broad and has a very nice range. From idle to redline, in my view the way it should be. The down side to this is the TB has a rather stiff spring which makes driving around town alittle odd. The linkage itself is also a bit odd in its function thus adding to the problem. I'm thinking the minivan tb bracket might solve this problem as it would get the angles right. Also be we aware of the different IAC the 4.3 TB uses. The DIS also doesn't get bolted to the upper manifold. The new MAP sensor can be used and read correctly. I also used the that other port by egr port for the Vacuum modultor and the fuel pressure regulator. The separation line for the IAC chamber must be filed down. as there is no idle air routeing on the tb or adaptor. As of now the TB cable bracket bottom leg had to be shaved down a specifc length. The cruise arm had to be bent downward so the Servo could operate it effectivly, I used a cable end from a 440-t4 TV cable and a throttle stop from Autozone to make this work. I also noticed the PCV valve elbow was too short so that was replced with a longer elbow. The opening is 4inches, For now I have the rubber quick plumbing reducer on it going to a 3inch pipe to a cone filter. Unfortunately I cannot use my coffee can anymore which offered stock routing and filtration. Also note the the neck by the fuel pressure regulator has to be lightly shaved down. I will get more pics up soon. In my view this manifold looks like hell but no doubt it is well engineered. Solving alot of power problems, now we finally have a pretty good balance on the bottom end and upper HP. The craftsman of the TB adaptor's email adress speeddemon1312@yahoo.com.

[Manitcor]

RE: Installed the 3500 manifold

nice work man, so you planning on making a few of those adapter plates? what did you fill in the IAC with?

[SappySE107]

RE: Installed the 3500 manifold

Im hoping to have the adapters made up once I get a plenum and TB to get the specs from. I want to have the adapters on the store and the guy currently making them sells them for 80 bucks and does them by hand.

Im looking forward to retuning this setup on the dyno

[v6h.o.]

RE: Installed the 3500 manifold

Looks good. I have to concur with your ass dyno. I felt roughly the same changes when I did mine.

[MidnightriderZ24]

i noticed a good jump in lower end grunt and top end. lorenzo, as for the throttle being stiff then soft, what i did was cut a notch in where the cable attaches then theres more leverage on it so it feels like the stock 3x00 tb, trust me it took ALOT of tinkering to make it work easy. i have some work in progess pix of the adapter plate.

[El_Diablo]

aproxamatly how much do these intake manifolds cost new? and used?



im thinking spacers (such as these) between the LIM and UIM would help with the fitment issues?

[Manitcor]

check out http://www.car-part.com thats where I get most of my stuff for this kinda thing.

[bszopi]

IIRC, you can get a 3500 plenum new from GMPD for ~$140.

[badz24s]

I looked on gmpd yesterday and it was $140 retail, but they are selling it for $99.

[El_Diablo]

check out http://www.car-part.com thats where I get most of my stuff for this kinda thing.

i know about that site but they didnt have any matches

[Manitcor]

i managed to find a couple but none for $99 thats a real good price

[badz24s]

here is the part number for the 3500 plenum GM PART # 12583460

this was posted under the topic "3500 intake installed on 3400 lower manifold"
I entered this part # on gmpd and it was $99 and some change.

I'm not sure what people have paid for their's thru car-part.com, but I think that a pretty good price for a new one. I definitely wasn't expecting it to be that cheap!

I want the extra power it gives, but it is just so ugly. I don't really like the fins(or whatever you want to call them) on the top.

[badz24s]

just checked it again and this is what I got:

GM PART # 12583460
CATEGORY: Engine Fuel Intake Manifold
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $174.88
OUR PRICE: $99.67
DESCRIPTION: MANIFOLD

Can anybody verify if this really is a 3500 manifold and if so, what car it is for?

[Manitcor]

tthat looks right to me, average price on car part is $125 for a used one.

the fins while looking ugly may acutally serve a purpose. as we all know, the plenum on pushrod 60v6 engines with stock intake piping get quite hot after running for a while. Its possible the "fins" serve as a way to increase the exposed surface area of the plenum to assist in heat dissapation. Kind of like a heat sink on a cpu. Its just my theroy though, not sure if there is any truth on it.

[badz24s]

good point, manitcor.
not trying to sound sarcastic, but if that's true, why did gm go from putting them on the older 3x00 and stop in 99 with the newer 3x00's?