Does anyone know what bolt size the harmonic balancer bolt is for a 1965 442 400 engine? Mine is missing need to replace.

 

I have several of them. $15 shipped for the bolt and washer. PM me your address

 

Eric, I learned from this thread that some of the 1965 cranks used the small bolt. To be safe, can the OP post a picture of the end of the crankshaft? The size difference should be easy to see. John

https://classicoldsmobile.com/forums...425-crank.html

 

i have cranks with both sizes. they are std machine threads. Washer is the hard find if you need one. pic will tell tale --

 

I don't know if the OP got the bolt they needed or not. But here's a picture for reference, they are both 330 cranks and the right hand one shows the smaller bolt hole than the more common larger one on the left.

DSCN7818.jpg

 

Sure did not know that one. Thanks for posting. I only have the big bolt

 

I will have to look at my 64 330 crank, betting it is the small bolt.

 

Sorry took so long. Haven't gotten bolt yet. I tried taken pic

 

I can't tell for sure but I think you need the small bolt. I only have the large one.

 

Is hard to tell. To me it looks like the bigger one. Lol

 

If you compare how much material is between the keyway and the hole it looks like the bigger bolt is needed.

 

Exactly what I was trying to do. I think the same. Bigger bolt

 

Place a tape measure over the hole. Looks like a large to me too.

 

Sent PM