Hot Rods Buick Nailhead question

What are you guys using for valve Cover bolts on aftermarket Buick Nail head valve covers?

What size and thread bolts?
I know some guys are making their own out of all thread.

 

I used St St bolts and I think they were 5/16 UNC by 3 1/2 long as I had a heap of 3" bolts but had to make a special trip to the bolt shop just for 4 bolts. If I remember tomorrow I'll pull one and measure.

 

5/16" SS all thread x however long you need for aftermarket covers. Should be long enough for the rubber washer and full thread engagement of a SS nylok nut.

 

If you cut the all thread the right length, you can use SS acorn nuts and SS washers to dress it up.