How do you change valve seals in a 5.7 350 motor?

Answer 1

its a little tricky if you have never done it you might wanna bring it to a shop but you need some special tools if your doing it in the vehicle if you need more info just have to specify in the car or out and motor in it or or engine disassembled

Answer 2:
You simply slide them on the valve stem, U side down (Cup down). The hard part is getting to them, and in BOTH cases you need a valve spring compressor (special tool).

On the car:

1. Remove the Valve Covers (and anything else in the way),
2. Disconnect the COIL and or module to ensure the motor will NOT start!
3. Run the piston to TDC for "That cylinder,"
4. Hook up a spark plug to air hose adapter (special tool) and supply at least 120 psi to the cylinder during the whole of the operation,
5. remove the rocker arms for both valves,
6. Remove the push rods if necessary,
7. put the valve spring compressor (not the C clamp style) on the head,
8. compress the valve spring and remove the retainer,
9. slowly release the tension on the valve spring,
10. pull off the old valve seal (if scarring exists the valve guide MUST be replaced - also check for excess movement of the valve stem in the guide),
11. replace the rubber valve seal (cup side down),
12. replace the spring (springs),
13. compress the spring,
14. use NEW spring retainers and replace the old ones,
15. slowly release tension on the valve spring (beware a retainer that is NOT locked into position),
16. repeat on the next valve for that cylinder,
17. remove the air hose.

Off the car:

Follow all procedures above, eliminate steps 3 & 4 - substitute C clamp valve spring compressor for step 7.

NOTE: if the retainers or valve spring will NOT separate; use a FLAT punch slightly smaller than the valve stem, and lightly tap it with a hammer (hitting this too hard will cause the valve to hit the piston and bend).