How Long is Factory Small Block Camshaft Bolt?

I have a one inch long bolt for my 340 camshaft. But after going through the special washer that does not leave a whole lot of thread contact with the camshaft. Just wondering if anyone knows for sure the correct length? Thank you.

340 would have a fuel pump eccentric on that bolt also.

Dibbons said:

I have a one inch long bolt for my 340 camshaft. But after going through the special washer that does not leave a whole lot of thread contact with the camshaft. Just wondering if anyone knows for sure the correct length? Thank you.

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Hi, I no longer have this so I can't measure it, but maybe these pics will help you.

Dibbons said:

I have a one inch long bolt for my 340 camshaft. But after going through the special washer that does not leave a whole lot of thread contact with the camshaft. Just wondering if anyone knows for sure the correct length? Thank you.

Click to expand...

The original camshaft sprocket lock bolt for the LA small block engines (including 340) is a 7/16"-14 grade five bolt, 1-1/16" long with a 5/8" head. The sprocket fastening includes the cupped washer and fuel pump eccentric.

The following images shows an original bolt with a measuring tape:


There can be a slight variance of less than one thread width over years and manufacturing batches as seen in the following image:

The two bolts on the right are slightly shorter than the three on the left.

All of the pictured bolts were made by the same manufacturer:

I've seen some photos of four pieces: bolt, regular flat washer, special large conical washer and eccentric. I am beginning to believe the regular flat washer is an invention of some of us whereby the factory only used the special washer with the bolt. Thanks for clearing the issue up for me (that extra 1/16th of an inch is a good practice but hard to find off the shelf).