Just bought the car about a month ago and am thinking the heater is not the best but gets the job done. After reading some posts I see there is possibly a 180deg thermostat and a 195. My temp gauge sits about 2 clicks left of center and some with known 195 state gauge sits straight up. If I decide to replace thermostat with 195 should a person consider the affect this may have on leaking manifold gaskets? I have small leak on top right now am just riding it out. Increasing temp may increase pressure. Am I corrct in that ssumpton?

It does increase pressure to an extent. Its more like the coolant is expanding as it gets hotter.

Downgrading to a cooler t-stat more than likely will not prevent your LIM bolt from leaking. The coolant is still going to get hot, and it will expand, which means it still has to go somewhere, and that one bolt thats not sealed is going to let it get by.

Some people like to run cooler t-stats in the summer time to keep engine temps down, and change them back in the fall-winter time.

If you think your heat isn't getting hot like it use to, it may be time for a flush of the heater core and or possibly the entire cooling system. Any idea from the previous owner about when it was done last?

The radiator pressure cap should maintain the same pressure in the system. (sorry Mike)

There will be more heat, but in our experience the gasket doesn't appear to degrade any quicker with the stock 195F stat over the 180F stat. Same with the upper intake. If you are naturally aspirated .. it doesn't seem to change with a different temp stat.

Thanks for updating my memory Bill.