Carb help needed kz550/zx550

Ok so I've changed the engine in my 81 kz550 to an 84 zx550. Now here's my problem the 81 used tk22 carbs which has a fuel line and a return line that go to the petcock from the carbs pulse vent lines and vacuum lines. But the zx550 carbs are tk27 which don't have the return line. So now I'm not sure what to connect the return line on the petcock to. Can the vacuum lines be used there cause I was planning to eliminate the air valve switch.

Could you possibly mean the vacuum diaphragm port on the petcock? The one that actuates the bladder and pushes fuel to the carbs?

If so, then I would assume that any source of vacuum would be okay to use.

Yeah, no "return line" for fuel. There is a fuel feed line and a vacuum line which pulls the petcock open and allows fuel to flow. Find some positive vacuum source from the carbs (not a vent line) and connect that to the petcock.

I figured by removing the evaporative emissions system I would just run the vacuum lines to the petcock. But if you look in the manual the vacuum lines go to the emissions system and the fuel return line (That's what it's called in the manual) goes to the petcock from the tk22s which the the tk27s don't have.
Wasn't sure if the 81 and 84 have different petcock cause on the 84 the vacuum lines and fuel return line go from the emissions to the tank.

On the ZX550, there are 2 different tanks. One is a CA Emission Tank, shown in your picture with rear venting and overflow ports that the other doesn't have. Hard to find a CA Emission Tank, as most are the other.

There are "T" vents, between carbs 1&2 and 3&4 and they should go to filtered air. Do not cap these off.

Just run a line from your tank to the carb inlet, and one of the vacuum lines from the carb, to the petcock vacuum port. Cap off the remainder.

Are you planning on running the airbox, or using Pod Filters?

That's what I thought I needed to do just wasn't sure with the different carbs. Running the airbox.
Thanks
Jeff