Briggs & Stratton does not recommend the addition of an oil filter to an engine that wasn't originally equipped with one. A special factory-installed mounting nipple is required to accept an oil filter. The process for attaching the mounting nipple cannot be duplicated in the field, therefore, it is impossible to add an oil filter post-production.
If you need any further assistance you may consider contacting your local Briggs & Stratton Authorized Dealer. This Service Dealer has all the information relating to Briggs & Stratton warranty information, engines, short blocks, parts, prices, service, specifications, proper fit, etc. To find our "Best-of-Class" dealerships, look for our Master Sales & Service Dealers (MSSD).