I was swapping out the thermostat the other day and found a hold missing its bolt on the drivers side of the engine just under the throttle to the carb. I have no idea what it does or if it is vital for the engine, can anyone help. I can get a better pic if needed.

 

Nothing's missing. It's an UNUSED bolt hole in the intake for your application. Way back in the old days they used it to attach a big-ol' bracket for ancient axial-style A/C compressors. You're good to go.

 

Alright thanks! I hate to be paranoid about it I just had no clue what it was for and it was freaking me out. Thanks again!

 

you should be twice as freaked out as you are- there is another hole over there somewhere that serves as the mounting point for the other leg of the old AC bracket...

 

I don't think I even want to look haha, I'm honestly tempted to go get some bolts to fill the holes so if I forget I won't panic again.

 

It was also used as the attachment point for a brace for the later R-4 compressors, and in fact that bracket would have been on your car at one time.

 

Sofa- you're thinking of the very similar looking FRONT hole. The one that looks just like it but is in front of the two center intake manifold bolts. That front hole takes the A/C support brace in later cars that use radial-stye compressors.

Neither hole will leak anything. They both go through to the intake flange, but they dead-end against the intake gasket.

 

No... there is most definitely a bracket that goes there. It is a piece of about ½" bar stock with an eye stamped into the end that goes to the intake, a coupla bends, and a little flag welded on with the other bolt hole, that bolts on top of the AC bracket.