Need L20B exhaust manifold

[eat_more_drift]

Curious to see if anyone has one of these lying around.

 

Would have to ship to Houston, TX 77080

 

Thank You

[datzenmike]

'75-'77 or '78-'80. There are two type. Both are 4 pipe into one outlet.

 

If you have an early one with U67 head, the ports are square. The '78 and up are W58 head and round port.

 

If you have the U67 or A87 or any square port head on your L20B, you can use the stock 510 exhaust manifold and down pipe.

[metalmonkey47]

I have one. Gotta go find it and look at it.

 

 

Like mike said though... do you need round or square port?

[eat_more_drift]

Sorry, its an 80's engine

[datzenmike]

That could only be from an 1980 720 truck. (last year for the L20B) It should be a W58 head with round ports. Better check, as all L heads can be interchanged. After 30 years anything could be on there.

[eat_more_drift]

What are the differences in the engines? Why didn't they make all l20b engines the same?

[datzenmike]

Emissions likely drove the changes.

 

The later '78 and up heads with the round exhaust ports have round steel liners in them.

 

As you can see they are held away from the port walls so that they absorb exhaust heat and glow red hot when driving. The L20Bs had air injection pumps that supplied outside air into each exhaust port to mix with the outgoing exhaust. Any unburnt gas now had oxygen and a red hot liner to ignite it and burn it off.

 

The W58 head also has two holes in them to supply hot coolant to the intake runners to warm them and keep at a more even temperature. This worked both ways and actually 'cooled' the intake in the summer when under hood temps soared. Emissions are much easier to control when the motor works through a steady range of temperatures. The earlier U67 heads did not have this and relied on the intake and exhaust manifolds being bolted together and hot exhaust being directed onto the bottom of the intake to 'warm' it. Not the best idea they ever had.

 

 

.

 

 

 

 

.

[eat_more_drift]

Still need an exhaust manifold for my 80 L20B W58.

[Z-train]

Round port?

[tdaaj]

W58 would be round port yes

[eat_more_drift]

Correct, I would need a round port exhaust manifold. In good condition of course seeing as the one I have is broken.

[eat_more_drift]

Also need the down pipe

[KlassicMotion]

Are you still looking? I will have to check see if I have one.

[eat_more_drift]

I found one, thank you