When using the single-vacuum distributor, the vacuum hose runs from the vacuum port on the left side of the carburetor to the vacuum canister on the distributor. In that case, the vacuum port on the rear of the carburetor must be plugged.
For most cool season grasses and for folks living in northern climates, the best time to plant grass is in late August, early September. Depending on exactly the climate you have and the type of grass seed you're planting.
There are three ways to plant grass: with seeds, sod or plugs. Seed lawns in late summer, early fall or in April or May. Soil needs to be warm when seeded. Seeding will take more time to grow a lawn. Sod is more expensive than seed, but will create an instant lawn. Sod can be put down at any time.