On the 305 carbed, can the guides be replaced without removing the heads? My mistake meant to say valve seals

 

Yes, seals can be replaced with the heads on the engine.

 

Just need air and a spring compressor. Be sure that they air supply isn't lost when doimg so or you will be chasing a valve. That bites by the way especially when on the last valve. Seems it brings new meaning to a dropped valve lol.

 

Or you can stuff rope through the spark plug hole until you fill the cylinder enough to hold the valves up. Worked for me.

 

oooh, very creative, i like

 

Uh, no. Valve stem seals yes, but not valve guides. Way big difference....

 

If you do the "rope trick", pull all the plugs so you can turn the motor over by hand. Stuff as much rope in as you can, then turn the motor till you feel the resistance of the piston pushing on the rope. Now you know the valves are pushed up snug.