been thinking the same thing lately! I'll be watching to see what you learn.
Thanks for asking.
Well, got to looking in the Clymers manual, and it looks like it would simply be a matter of removing the pressure switch, behind the front cover and beneath the water/oil pump, and replacing it with an adapter, line and gauge.
Off hand, I don't know what size that would be, but it seems likely that there's adapters out there that would fit. Then it would be a matter of running a line to a gauge. Where were you thinking about mounting that?