79 pickup dual tank vent and fuel line routing

[1htsob]

Anyone know where I can find a diagram of the vent and fuel lines for a dual tank setup on a '79 K-10? The truck has dual tanks with 3 outlets out of each sending unit. The tank selector switch has 4 inlet and 2 outlet ports and there are two charcoal cannisters up front. I know the 3/8" outlets on the sending units are the fuel lines that connect to the two 3/8" inlet ports on the selector switch. The 3/8" outlet port on the switch goes to the 3/8" fuel line running along the right frame rail. The 1/4" outlets on the sending units go to the two 1/4" inlet ports on the switch. I believe these are the fuel return lines. This is where I get alittle confused. There is the one remaining 1/4" out let from the switch and there is a vent line on the frame right in front of this port. Therefore I assume this connects to that port. There are the two remaining 5/16" outlets on the sending units. Do these get connected together and head up to a cannister? Do I really need two cannisters or can I just tee the vent lines together into one cannister?
Thanks for any help in this matter.
Dan
72 Blazer, 79 K-10, 78 Blazer, 97 Blazer, 97 Silverado

 

[R72K5]

the smallest little oens are tank vent lines

the next oens up are returns

lrgest 3/8 are main lines to the fuel pump

cant help a on tank valve switch assembly hose routing though

trying to think of a dual tank chevy truck 73-up with evcerything still intact that i could look under for ya, hmm..

might have one soon to check out maybe, my old 83 k20 with original dual setup has one tank removed nowadays so that wont help ya too mcuh i dont think, but i could look anyways if ya want, all the lines should still be under there, just not connected to the a tank


good luck

 

[1htsob]

Thanks for the reply. No need to go look under another truck. When I was at the wrecking yard last week, I found a similar truck and was able to sketch up the routing scheme.