I recently changed the head gasket on a Briggs Quantum and while the bolts were out I gave them a good go on the wire wheel. Trouble is I think I ate into the thread because half of them don't want to tighten up. I may have damaged the thread on the block as well. Can anyone tell me what size and type of thread the head bolts are standard and also what size and thread type I should replace them with so I can tap a new thread. Also do I need to upsize all the bolts or just the ones that won't tighten.
Model 121702
Type 0191 01
Code 90121125

Last edited by Dave107; 06/11/19 05:53 AM. Reason: Forgot numbers