How to find what the engine size for my Ford F250 XLT Lariat
If all original try using a vin decoder. This should tell you what was put in it at the factory.
Most likely the 351 Windsor, they were in most 1987 F-250's
Search Ford F-250 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford F-250 Experts