How do you replace hydraulic lifters on a buick 3800?

To replace hydraulic lifters on a Buick 3800, first, ensure the engine is cool and disconnect the battery. Remove the intake manifold and valve covers to access the lifters. Carefully take out the old lifters, ensuring not to damage the pushrods, and install the new ones, making sure they are properly seated. Finally, reassemble the components in reverse order, ensuring all gaskets are replaced and torqued to specifications.