3500 Part numbers. MORE INFO ADDED.

[v6h.o.]

Marty and I have been talking since the thread on GrandamGT...

he asked for the PN for the 3500 upper. ive been wondering about that manifold myself for a while...

Brad can we have our own discussion on this over here?

Part numbers from the 3500:

Plenum: 12583460.
Lower IM: 12579767 (i just got the part number for this for Brad to add to the already large list of Manifold part numbers. its not needed with the 3500 upper)

Front Exhaust manifold: 12578139
Rear Exhaust Manifold: 12586683

i grabbed the rear manifold part numbers as they might be a cheap option for those wanting to split up the manifolds from the shit crossover setup and do a Dual exh or better manifold option on their 60v6.
(the 3500 uses separate front and rear manifolds with no crossover)

[RacerX11]

Thanks for ther numbers Colin. I will have to order one of these guys up to play around with.

I think the exhaust manifolds will prove to be very helpful for guys swapping a 3X00 into a Fiero.

Marty

[v6h.o.]

yeah i ordered one up today as well. i'll have to see what type of gains i can get out of it and if its worth it.

if i can when i dyno the car for tuning of the ECU i have maybe i'll do a comparision of the two... if i get time..

[Mars]

Excellent news Colin. I was also reading that thread. Make sure follow up on this, pretty interesting stuff.

Also, have you seen the front manifold? I mean under the heat sheild, How does it look under there? is it "log" style? or a nice flowing one like the 3400 rear one?

[v6h.o.]

I have pics in my folder of them (on vehicle) its a "header" style IIRC.

i'll dig through the pics and see if i can find any good ones.

unfortunatly when i changed dealerships back in Feb i went from a Chev Olds Caddy dealer to a Pont Buick Caddy GMC dealer..

i dont get to see any Malibu's or Malibu Maxx's to look at these things anymore. no-one with those cars have brought them in for service at our place yet either.

[v6h.o.]

no, dont have any good pics of the front manifold.

im wondering if the new plenum has more volume to it now that ive gone and looked through the pics again...

i guess we'll see what the under side looks like when i get it... here is a side profile shot of it:



hopefully we're not being duped into thinking its a large plenum opening and only a "gen2 style" where the top of the manifold is just filled in to look like one big thing with split runner hiding out underneath... i hope not. guess we'll see when i get my manifold next week. Marty and I are going to be the guniee pigs by the looks of it. :P

[bszopi]

John said that there is a fin or something inside to split the air and length the path to some of the runners or something. I dunno... guess you'll see when you get it.

[xxrollin]

Any idea if the heads are different? How bout valve size. Anything new on these other than manifolds in general. Is the front cover more less the same design, can we intergrate the new cover with the electric power steering or is it tied in to the ECU somehow. How bout the cam, is it still the hollow assembled cam found on all the roller motors available. I like the intake manifold but theres tons more info most are still waiting to hear. Anything??

[bszopi]

This is kinda off topic, but oh well. I'm an admin, I can do this...

People have seen the plenum for the 3500, and well as the ram-horn plenum of the 3.6DOHC and 3900. But has anyone seen this variation of the 3.6DOHC plenum? Kinda interesting...

[bbeck]

also, how is the 3500 mounted? similar to the 3100/3400?

[v6h.o.]

Yeah ive seen one of those plenums brad...


the 3500 uses the same style of motor mounts as a 3400/3100's.

[bluebomber]

Ahh, the lengths GM will go to so that they don't have to retire pushrods.
That 3600 pic looks quite a bit different then current 3100/3400s, it looks like the entire drive-belt system is rerouted, and they put the alternator in a [sarcasm] great spot [end sarcasm], I bet the 3.4 DOHC are seeing some resemblance there. If the numbers are where they expect these motors to be though, that will be cool. BTW, what are they planning to put the 3900 in?

[bbeck]

would these manifolds bolt up to a 2.8? if so, would I need the new oil pan? anyone tried to bolt them up yet? and what's the cheapest everyone has seen these motors go for? or anyone know of a whole wrecked car?

[bszopi]

Ok, here is the official response from GM...

-Did the cam keep the same profile as the 3400?

NO -- NEW INLET AND EXHAUST PROFILES

-What was the purpose of going to the box style plenum, thus shortening the runners by almost 3"?

TWO MAJOR BENEFITS -- IMPROVED AIR FLOW (WHICH EQUALS HP) AND IMPROVED NOISE

-Are the heads still the same as the 3400?

NO -- THE HEADS HAVE NEW PORTS AND COMBUSTION CHAMBER


So there you go. I'll see if I can't find some more info out, especially about the new cam profile numbers. And as far as the plenum goes, I kinda figured that it had something to do with noise....

[v6h.o.]

new head and chamber ports eh... hmmm. new cam profiles..


Compression Ratio
9.8:1

Camshaft Lobe Lift - Exhaust
6.9263 mm
0.2727 in

Camshaft Lobe Lift - Intake
6.9263 mm
0.2727 in


those are the only specs GM gives for the 3500 camshaft on SI.