The VHF FM band seems affected by the mica capacitors in the IF and discriminator cans and general opinion today is that you need to change them all out as a matter of course. The postage stamp things. It is over 70 years old and they seem to be suspect now.
If during alignment the IF cans have a good peak as they should I leave them alone. However if the peak is broad or on one end of the coil or the other, you will probably find bad caps. I have changed the caps in the IF cans of an SX 42 and it requires a steady hand and is not easy. They use the end of the capacitors as tie points for the coil windings in most cases.
Good light and a steady hand is required. Also for size, I suggest anyone look for 1 KV capacitors rather than the 500 volt versions to fit the bracket in place of those in the can. If you cannot find or have them, 1 suggest you get some insulation tubing to cover the leads in the necessary places.