The Porters are a difficult family to trace and although we share names trying to find the connection is somewhat fraught to say the least.My ancestor is also John Porter of Moorlinch but the baptism I have for him is around 1773. Jasper seems to have been a common name for both families. This John married Edith Mitchell on 25th Apr 1798. They had 5 possibly six children. Two of whom are called Jasper 1812 and John 1803. I have followed their descendants and there are no names that match yours. I am happy to share with you what I have. There is also another John porter you could contact. He lives in Taunton and his email is johnatcrossconnections.org.uk. We found that we were not connected but share all the names. He has done research on his family of Porters and there may be a connection for you there.
I dare say there is a connection between us all but it is further back than we are able to pursue