I recently had a lot of maintenance issues taken care of on the 312 Y block in my '57 Bird. In order to properly service the AT in a bird, you have to remove the engine.
The rear main seal had a very minor leak..
The Y blocks use the old style "rope" rear main seal, there is a new style seal available that we used..
New valve cover gaskets. You should also check the valley cover gasket.
I also had all of the below done.
New ignition wiring and insulators.
New soft pugs.
New water-pump... Many of the Y blocks have an anti cavitation plate between the pump and the timing case cover.. Over time the mild steel plate rusts out, which can lead to cavitation (air entrainment) in the cooling system.
Have the radiator boiled out, repaired as needed
New thermostat, hoses and coolant.
New fuel pump.. Make sure the new pump is compatible with alcohol based fuels.. It will say right on the box if it is... Do not accept a fuel pump that is not of current manufacture.
If the engine has not had the canister type of oil filter changed to the spin off type, do so while the engine is out..
I would also suggest that you put a Pertronix ignition module in the distributor..
I also put all new brake wheel cylinders and fluid in the brake system..
It had been seventeen years and 11k miles since all of the above had been done on my car... Most of the items replaced were generally out of their service life..
