Bolt size help

[john87442]

Ok so as I’m putting my 87 442 back together I’m always looking for the nuts and bolts I took apart. Now I will say the majority I have nicely bagged up and labeled however as I’ve been assembling the engine and brackets I’ve found it helpful to use the bolt gauge I’ve assembled from the hardware store (I’ll insert a picture).
To my question though as I’m trying to install the shift plate bracket for the lightning rods it screws into the same holes on the transmission hump, Ive tried every size and I’ll be damned if I can figure out what size they are nothing fits standard or metric, next I’m just going to tap new ones. If you know please help a brother out. Thanks in advance

 

[john87442]

Ok just to follow up I’ve found that it’s not a standard or a metric bolt but rather a machine screw that was used.
Just fyi for anyone in the future that might search.

 

[Sweet_Johnny]

Ok just to follow up I’ve found that it’s not a standard or a metric bolt but rather a machine screw that was used.
Just fyi for anyone in the future that might search.

Good to know, thank you. I've got a set of Rods that may see a car some day.

 

[78Delta88]

Most everything GM went metric thread with model year 1982 and after. However, still some holdovers, 3/8 course and 5/16 fine thread on and around engine, transmission and differential.