eat_more_drift Posted September 26, 2012 Report Share Posted September 26, 2012 Curious to see if anyone has one of these lying around. Would have to ship to Houston, TX 77080 Thank You Link to comment
datzenmike Posted September 26, 2012 Report Share Posted September 26, 2012 '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. Link to comment
metalmonkey47 Posted September 26, 2012 Report Share Posted September 26, 2012 I have one. Gotta go find it and look at it. Like mike said though... do you need round or square port? Link to comment
eat_more_drift Posted September 26, 2012 Author Report Share Posted September 26, 2012 Sorry, its an 80's engine Link to comment
datzenmike Posted September 26, 2012 Report Share Posted September 26, 2012 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. Link to comment
eat_more_drift Posted September 26, 2012 Author Report Share Posted September 26, 2012 What are the differences in the engines? Why didn't they make all l20b engines the same? Link to comment
datzenmike Posted September 26, 2012 Report Share Posted September 26, 2012 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. . . Link to comment
eat_more_drift Posted November 4, 2012 Author Report Share Posted November 4, 2012 Still need an exhaust manifold for my 80 L20B W58. Link to comment
tdaaj Posted November 4, 2012 Report Share Posted November 4, 2012 W58 would be round port yes Link to comment
eat_more_drift Posted November 4, 2012 Author Report Share Posted November 4, 2012 Correct, I would need a round port exhaust manifold. In good condition of course seeing as the one I have is broken. Link to comment
eat_more_drift Posted November 4, 2012 Author Report Share Posted November 4, 2012 Also need the down pipe Link to comment
KlassicMotion Posted November 6, 2012 Report Share Posted November 6, 2012 Are you still looking? I will have to check see if I have one. Link to comment
eat_more_drift Posted November 6, 2012 Author Report Share Posted November 6, 2012 I found one, thank you Link to comment
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