AIR Exhaust Manifold Thread Size

[William P.]

Hi , Could someone please tell me what was the origonal thread size for the holes that the tubes thread into .The ones that everyone forced pipe plugs into . I am restoring a set of manifolds for my 71 LT1 .Regards Bill

[Joe L.]

Re: AIR Exhaust Manifold Thread Size

Hi , Could someone please tell me what was the origonal thread size for the holes that the tubes thread into .The ones that everyone forced pipe plugs into . I am restoring a set of manifolds for my 71 LT1 .Regards Bill

Bill------


The thread size is 1/4-18 NPSF. This is a STRAIGHT pipe thread.

[William P.]

Re: AIR Exhaust Manifold Thread Size

Thanks Joe, I read where it was 1/2x18 but that didn't seem to fit .

Regardes Bill