Are the 3.0L exhaust manifolds a drop in for the 2.9L manifolds?

[nkemp]

Do the 3.0L exhaust manifolds fit in place of the original 2.8L manifolds? I know the port/block dimensions are the same but I was wondering about the point where the manifold attaches to the crossover pipe.

Has anyone done this? Results? I've heard the 3.0L referred to as the poor man's header. They seem to have a nicer flow than the originals.

I've done some searching herein and have not found an answer...so I thought I'd ask

[content22207_2]

No, manifolds are not plug & play interchangeable with the remainder of OEM exhaust.

They will bolt up to 2.8 liter heads no problem, but are shaped totally differently to mate up to a stock crossover pipe (plus they use a different style flanged connection):

43521

Owen Malbec is running a pair on his engine, but the remainder of his exhaust is custom, not stock.

Steve Stankewitz's engine is 3.0, but this gives you an idea what the manifolds look like bolted in place (3.0 and 2.8 exhaust ports are in the same location):

43522

Bill Robertson
#5939

[nkemp]

Thanks Bill.

Bummer for me. I have to decide what all to do while I'm fixing the 2.8's exhaust leak and I have a 3.0L engine sitting on a rack for a future day and thought maybe the exhaust manifold might work. The 3.0l's seem to have a better flow pattern than stock so it would have been an interesting experiment. It's not worth the energy to try to modify he exhaust to fit. I thought about the new exhaust header systems but the price seems disproportionate to the benefit.

Now on to plan B ... which is to figure out plan C.

Also ... they seem to be a tight fit. There does not appear to be much clearance to the frame.

[content22207_2]

There does not appear to be much clearance to the frame.

There isn't. They weren't designed for our engine cradle (there's a reason DeLorean manifolds are so compact).

I think Owen rigged up some sort of heat shield to protect epoxy on his cradle.

Bill Robertson
#5939

[JohnLane]

DeLorean manifolds are the same restrictive junk fitted to the Volvo B-28.
Replacing B-28 manifolds with those fitted to the three liter makes a seat of the pants improvement in a Volvo.
The conical flanges come right off with the chop-saw... The Miller MIG welder gets them to talk with .120" wall pipe which can be shaped as needed to fit.
Note... The three liter manifolds have a left and right side. They must be installed as pictured earlier in the thread or the ports will not match up.... Though the manifold will slide onto the studs.