454, 1987, lower oil dipstick Bolt

[Sgt Gus]

Bolt at the block is missing, and haven't figured out.
Google AI says 1/2" - 13, but no.
The power steering Bolt on front of water pump is that size.
Definitely seems 1/2", but finer thread.
Could be 1/2" - 14 npt, but that is pipe thread?
1/2" - 20? Seems to fine, but clearly I don't know.
Can't hurt to ask men. One damd Bolt.

 

[legopnuematic]

Got a photo?

I'm not a big block guy but a 1/2" bolt sounds rather large for a bolt on component. I'd suspect 3/8-16. Thats what (on small blocks at least) is used on the water pump/brackets.

 

[WFarm]

1/2-13 is coarse thread. 1/2-20 is fine thread.

 

[Ricko1966]

I imagine it's 5/16 18 which would be a 1/2 wrench size.

 

[Sgt Gus]

Ok, I agree with y'all. Thinking maybe I left in engine when I took to shop so I wouldn't loose it. That would be something stupid I would do.

 

[Sgt Gus]

Here are picks,
1st two shows open hole.
3rd shows me holding larger than 3/8 - 16 stud.
4th shows the 3/8" - 16 on left with larger stud I held in there on right.
5th show me starting the 1/2" - 13 in the hole. To coarse.
Last below, shows the lower portion of dipstick next to bolt which clearly won't fit.

 

[Sgt Gus]

Crazy, yes? Maybe there was a stud with smaller thread on top?

 

[Sgt Gus]

Well, I looked at my fabulous pics. Zoomed in...and PO didn't have a bolt there. Least I'm not stupid.
Guess I can put the RTV pooky on it and move on.
I'm thinking it might be some stud with reduced thread like the one in the pic but...bigger.