Depends on whether the 300C engine has a pad for vacuum
pump. Check the faa type certificate data sheet for the
engine to verify this. The engines originally shipped with that
model didn't have the pad. Probably the plane has been
updated. I'm pretty sure a 300D does have the pad; I take care
of a plane with that mod here in Fort Collins.

You would need the pump and probably a vacuum regulator.
Make it exactly like a newer model that had this stuff; it
will make doing a field approval much simpler; you will have
very good "acceptable data". When the fed stamps block 3
of the 337, that becomes approved data.

If someone has an STC, that would be easiest. The attitude
on field approvals varies depending on your FSDO.

Bill Hale A&P

gt wrote:
I would like to make my 1960 Cessna 172A IFR. Currently, I have only
venturi vacuum. My A & P stated that as there is no STC for a vacuum
pump intall, I need a form 337 field approval...I think it is form 337,
I could be wrong on that. Does anyone have information relating to
STC's and field approvals for vacuum pump installations on a
Continental 300-C?