If you have an OHV engine, you can do this while the heads are on the engine in the vehicle. You will need: air compressor, spark plug fitting, valve spring removal tool, small hammer, and a magnet is advisable. Trust me, you will most likely drop at least one of the valve spring locks. If no air compressor, you can use some small rope. Pull the plugs, remove the valve covers, air or rope in the cylinder, turn to compress rope (if using) to hold valves closed, remove valve locks while holding valves down with tool, remove springs and old seal, install new seal, and reassemble. I like to use stock 289 seals. They are inexpensive and work great. I have done this many times, even on small block Chevys to cure a seal leaking problem. Any questions, just post.
