When son pulled all the vacuum lines off the truck there was a small round "fitting" that has one hose fitting on one side and two on the other. I thought it was a check valve but I can blow through it. What is it and do I need it. There are also 2 vacuum canisters under the hood, the old juice can and a round one the size of a softball. Do I need to keep them both?

Also we have a 1406 Edelbrock carb on it and they say to hook the crank case breather to the port on the front of the carb and the brake booster to the back, My manifold has a fitting at the very back that has the vacuum for the brakes, transmission and something else (I think heater controls, trucks not here) coming off it. Since I don't need the port on the carb for the brakes can I hook the crank case breather to the port on the back of the carb where the brakes should go? Just makes for a cleaner fit.

I have vacuum lines for my dizzy, brakes, transmission and heater, are there any others needed?

 

The 2/1 check valve sounds like the check valve for the heater controls. The side with the single port connects to manifold vacuum. The 2 ports on the other side connect to the heater controls and a vacuum reservoir.

One of the vacuum reservoirs is the vacuum reservoir for the heater controls. The other might be the vacuum reservoir for the cruise control servo, if equipped. If the truck never had cruise, then it might have been the original reservoir for the heater controls, but was just never replaced when the newer and smaller reservoir was installed. The original reservoirs look like a coffee can; the new replacement styles look like a softball as you have described. You do need the reservoir (along with the aforementioned check valve) for the heater controls to operate properly. This setup is in place because all the heater controls are vacuum controlled, but vacuum drops off under various conditions. This keeps the vacuum to the heater controls strong and somewhat regulated. Otherwise you'll see odd behavior, such as the heater controls dropping to deforst mode when you punch the gas.

At first glance I don't see a problem running the PCV valve (or breather filter, depending on the direction of your setup) off the rear port instead of the front port since they should both be manifold vacuum sources. However, if it were me, I'd give Edelbrock a call just to make sure there's not some odd reason why you should use the front; they may have their own reason for recommending the front port. I used the front port for my PCV valve because it didn't really get in the way for my setup. If you do find it's okay to use the rear port, you'd just need an NPT to barbed hose fitting.

The only other vacuum line you'd need is for your EGR system, if equipped.

 

Thanks FMC400

I should have mentioned that there is no pollution control on the motor.

It does have cruise control so that would be the reason for the 2nd canister.