Before the trans is bolted up to the back of the engine, and the converter to the flexplate, the torque converter must engage fully onto the transmission's front input shaft. To do this, make certain that the converter is perpendicular to the front of the trans and centered on the input shaft. Then spin the converter by hand several revolutions while pushing it toward the rear of the trans. After a few moments there should be two separate clunks as the inside of the converter engages into position onto the shaft. Once the converter is mounted correctly, there should be approximately 1 inch between the front of the converter and the face of the trans case and the converter should spin freely by hand.
Carburetors that have been used and then shelved for more that a few months may need to be rebuilt or repaired before reinstallation. A typical problem is caused when the carburetor piston's (used on some models) soft seal shrinks and no longer touches the bore. This condition causes very hard starting because a sufficient fuel shot is not produced on start-up or acceleration. The solution is to simply replace the piston assembly (or seal) with a new part.
This older-style Quadrajet carburetor uses a sinterized bronze filter, and later-style Quadrajet carburetors use a paper element. What's important is that the filter is installed in the correct direction. The bronze filter installs in the direction shown, and the later paper element installs so that the attached round seal directs into the fitting. Also note the spring installed into the carburetor to load the filter against the fitting.