Hey, just saw LT1guy's ebay listing of the 3.4 intake manifold and plenum package... the intake manifold looks almost exactly like the 2.8 one I have in my basement, minus the cold start injector. You guys that did the swap, how close are they to being the same? I suppose it might closely resemble the 3.1 intake manifold sine there's no CSI...

 

for all non-cold start injector cars, it's the same damn thing.

 

Cool, thanks for the skinny! And to keep anyone from asking, nope, I've got no projects in mind, I was just curious. I actually think it's smart of GM to be able to get away with re-using the same part from 1990, and the same "basic idea" part since '85!

 

actually...i thought the 2.8 intake manifold was 2 pieces...and the 3.4 was only one...and thats why most people who do the 3.4 swap keep the 2.8...because its easier to port and polish being in two pieces...maybe i read wrong or am remembering wrong...i may only be 18...but that doesnt mean i havent already killed my short-term memory...now what was i talking about??? oh yeah...could someone clear this up???

 

The 3.4 SFI upper intake/runners is different than the 2.8/3.1s

The base intake should be the same, or close to it.

 

Functionally, its the same...we would have used it on Redraif's 3.4 had we not already ported the 2.8 base. The 2.8 intake is three pieces (base, runners, plenum); the 3.4 is two (base and runners/plenum). I can see no advantage to running the 3.4 upper on a 2.8; it looks just as restrictive, yet much harder to port due to the design. Plus, it may need some clearancing at the rear for the distributor, though I didn't check that.

 

the upper 3.4 manifold will most definately not clear the distributor. No where near it, w/o some serious modification to the rear crossover. Also must use the 3.4 er tube w/the manifold as it's in a different location than the 2.8/3.1s.