Last year i Had the stock pump and it was at 38PSI and this year after the walbro 255 its at 43 . As i was typeing this I just realized that this winter I also but a new cam in and maybe the lower vacume it making it incorrect? Can this be adjusted. Its at 47 PSI Line disconnected. 112 LSA for the cam. Pulling 12-14 HG's of vac.

 

The cam can affect the readings if those readings were taken with the vacuum line connected... and those numbers look to me like it was connected. The pressure would go up with less vacuum, its a direct linear relationship since both values are measured in PSI. Sounds like you lost 5PSI of vacuum