Need urgent help with a screw I do not know which will fit
The screw on the engine for the servo pump bracket, is this a special screw I can not find one that fits ?

Engine 1971 / 455





445

 

The original was a double threaded stud and spacer as in the picture.

 

Hi thank you so far I have founde the 2 bolts in picture
please can you advice me which goes where , please ;-)

 

That looks like the bolt for the power steering bracket that goes in the first exhaust manifold bolt hole. In your case headers from what I can see.

 

Can you provide a clear picture of the writing on the head of the bolt that is shown? Writing on the head of a bolt usually indicates a metric thread. SAE hardware uses a marking system of dashes. The best I can tell it looks like a metric bolt has been threaded into an SAE threaded boss on your 455 engine. Certain size/pitch metric bolts will thread into an SAE thread but will strip the threads when tightened.

 

You all need to look again. The bolt in question is the one that goes through the bottom of the PS pump bracket into the side of the block. It goes into the frontmost of the three motor mount holes in the side of the block and uses the large spacer. It is 7/16-14 thread by 1.5" long and it is most decidedly not a double ended stud. It's bolt number 9419077 in this diagram.

 

Yes, I thought the same when I looked at the picture.

A 10 mm bolt will fit into a 7/16-14 tapped opening with about 1 mm to spare on the OD and about 0.7 mm on the core diameter. The pitch is smaller by only 0.3 mm, so a heavy hand could mess up those threads.

An 8 or 12 mm bolt will not fit.

 

My mistake, sorry for the misleading answer.