exhaust manifold nut size

[86-accord-lxi]

When I first bought my lxi , I noticed that 4 of the 7 nuts holding
the exhaust manifold to the engine were missing. I have looked all over
through my tool boxes and the tool shed and cannot find one damn
nut that will fit. This is really eating at me, don't know why, but it erks me.
exactly what size are the exhaust manifold nuts on our cars?

[POS carb]

I think they're 14 MM heads but the thread is different, plus they're supposed to have thick washers behind them. Grab a handfull from the junkyard.

[86-accord-lxi]

I thinkk the head is 12mm, I need to know what size the thread is.
Your right, I'll just grab some at the junkyard.