diff --git a/awx/main/models/inventory.py b/awx/main/models/inventory.py
index 7d9069e4f0..5121f081ed 100644
--- a/awx/main/models/inventory.py
+++ b/awx/main/models/inventory.py
@@ -1158,13 +1158,6 @@ class InventorySource(UnifiedJobTemplate, InventorySourceOptions, CustomVirtualE
             raise ValidationError(_("Cannot set source_path if not SCM type."))
         return self.source_path
 
-    def clean_source_vars(self):
-        injector = self.injectors.get(self.source)
-        source_vars = dict(self.source_vars_dict) # make a copy
-        if injector and self.source_vars_dict.get('plugin', '') != injector.get_proper_name():
-            source_vars['plugin'] = injector.get_proper_name()
-        return json.dumps(source_vars)
-
     '''
     RelatedJobsMixin
     '''
@@ -1369,13 +1362,21 @@ class PluginFileInjector(object):
         """Returns a string that is the content for the inventory file for the inventory plugin
         """
         return yaml.safe_dump(
-            inventory_update.source_vars_dict,
+            self.inventory_as_dict(inventory_update, private_data_dir),
             default_flow_style=False,
             width=1000
         )
 
     def inventory_as_dict(self, inventory_update, private_data_dir):
-        return inventory_update.source_vars_dict
+        source_vars = dict(inventory_update.source_vars_dict) # make a copy
+        proper_name = self.get_proper_name()
+        '''
+        None conveys that we should use the user-provided plugin.
+        Note that a plugin value of '' should still be overridden.
+        '''
+        if proper_name is not None:
+            source_vars['plugin'] = proper_name
+        return source_vars
 
     def build_env(self, inventory_update, env, private_data_dir, private_data_files):
         injector_env = self.get_plugin_env(inventory_update, private_data_dir, private_data_files)
@@ -1463,6 +1464,7 @@ class gce(PluginFileInjector):
     def inventory_as_dict(self, inventory_update, private_data_dir):
         ret = super().inventory_as_dict(inventory_update, private_data_dir)
         credential = inventory_update.get_cloud_credential()
+        # TODO: Align precedence of ENV vs. inventory config w/ Ansible behavior
         ret['projects'] = [credential.get_input('project', default='')]
         return ret
 
diff --git a/awx/main/tests/functional/api/test_inventory.py b/awx/main/tests/functional/api/test_inventory.py
index a04a68c9bb..5bad1b6f30 100644
--- a/awx/main/tests/functional/api/test_inventory.py
+++ b/awx/main/tests/functional/api/test_inventory.py
@@ -456,38 +456,6 @@ def test_inventory_source_vars_prohibition(post, inventory, admin_user):
     assert 'FOOBAR' in r.data['source_vars'][0]
 
 
-@pytest.mark.django_db
-@pytest.mark.parametrize('source,source_var_actual,source_var_expected,description', [
-    ('ec2', {'plugin': 'blah'}, {'plugin': 'amazon.aws.aws_ec2'}, 'source plugin mismatch'),
-    ('ec2', {'plugin': 'amazon.aws.aws_ec2'}, {'plugin': 'amazon.aws.aws_ec2'}, 'valid plugin'),
-])
-def test_inventory_source_vars_source_plugin_ok(post, inventory, admin_user, source, source_var_actual, source_var_expected, description):
-    r = post(reverse('api:inventory_source_list'),
-             {'name': 'new inv src', 'source_vars': json.dumps(source_var_actual), 'inventory': inventory.pk, 'source': source},
-             admin_user, expect=201)
-
-    assert r.data['source_vars'] == json.dumps(source_var_expected)
-
-
-@pytest.mark.django_db
-@pytest.mark.parametrize('source_var_actual,description', [
-    ({'plugin': 'namespace.collection.script'}, 'scm source type source_vars are ignored valid'),
-    ({'plugin': 'namespace.collection.script'}, 'scm source type source_vars are ignored invalid'),
-    ({'plugin': ''}, 'scm source type source_vars are ignored blank'),
-    ({}, 'scm source type source_vars are ignored non-existent'),
-])
-def test_inventory_source_vars_source_plugin_scm_ok(post, inventory, admin_user, project, source_var_actual, description):
-    r = post(reverse('api:inventory_source_list'),
-             {'name': 'new inv src',
-              'source_vars': json.dumps(source_var_actual),
-              'inventory': inventory.pk,
-              'source': 'scm',
-              'source_project': project.id,},
-             admin_user, expect=201)
-
-    assert r.data['source_vars'] == json.dumps(source_var_actual)
-
-
 @pytest.mark.django_db
 @pytest.mark.parametrize('role,expect', [
     ('admin_role', 200),