[aigel]

If the engine is out, I'd remove all of them. If they break, drill them out. That steel has become very brittle from heat cycling over the years and if you have them break later while the engine is in the car and you are doing maintenance on it, you will regret not putting all new hardware while it was easy.

If the engine is in the car, forget about it - just reuse.

One comment on the double nutting ... you can put a box end wrench on the bottom nut if you put it on there from the get go.

George