Head bolt sizes????

[Chris McDade]

I need to get a tap so I can re tap all the holes on the block.
What size are the head bolts on these cars???

Thanks in advance

 

[TurboRegal84]

Thread size is 7/16 Coarse...take a headbolt with you to double check the size...fubaring the threads would not be good.

 

[Chris McDade]

Thanks Herb

 

[FJM568]

DON'T buy a standard tap to re-tap the holes with!!! Make sure you get a cleanup tap(slightly smaller thread pitch than a standard tap so you won't remove any material, just cleanup what is there)...If you remove any extra material, the thread pitch will be too big and you will have loose threads...You should be able to get them from like Summit or Jeg's or possibly your local speed shop, or a local tooling supply store...It is a specialty tap and IT IS NOT THE SAME as the taps you can buy at the hardware store...

 

[TurboTR]

Well good ol' Sears hdw sells a nice little rethreading set (not cutting, rethreading per above). I have one, well worth it IMO.

TurboTR

 

[FJM568]

Oh yeah, forgot about good ol' Sears...

 

[TurboRegal84]

Jim, I used a reg old 7/16 tap that I got from Sears to trace the bolts....It did not remove any metal material, but it did do a hell of a job getting all of the left over sealent that was used the last time the heads were off......

 

[Chris McDade]

Good point there guys..I will swing by sears on the way home.

Is it just 7/16 or is it 7/16-?

Thanks

 

[QuickWrench]

7/16 - 13 (Coarse)

 

[FJM568]

Um, no....

It's actually 7/16-14 for coarse threads