Newer Motor replacement is in 5.0 sterndrive

[crazy charlie]

Had one of my 1988 5.0lx 4bbl replaced with a Vortec 5.0 .Went in better than anticipated.slight clearance issue at first so they pulled the spacers under the risers and voila ,clearance!! Motor looks good,idles good,starts right up.It might have a 160 tstat and I am used to and always had 145 so the installer is looking into that for me .Strange temp gage issue since the install.When motor is off,cold and about to start,the temp gage is burried below the lowest reading.Was never in that low of a position prior to the engine change.My guess was the sender was not compatible.Installer was not concerned however I am.I dont know if it is giving me the correct reading.10 mins on muffs in 45 degree weather,risers cool,upper hoses cool ,lower slightly warm.Shot a temp gun everywhere and nothing was hot,mostly 100 readings and a 130 closer to circulator pump.Sure dont want that temp think in the back of my mind.All else looks good for now.Got a good deal on a nice newer motor and they didnt jack up any pricing on the removal and install mods.Charlie