Re: Adding extra 3/8 head bolts/studs on a 401 block INFO needed

["Bob" <masheen@xxxxxxx>]

Armand, I hadn't thought about the material type we were applying a thread 
to and you are certainly correct.  However, this metallurgical 
characteristic won't hinder the use of a stainless steel helicoil insert 
which would then leave the option of a course/fine thread open regardless of 
the material type.  Please enlighten me if I'm wrong.
As for tapped holes in aluminum, I would helicoil every one I came across. 
Reason being that a hardened steel bolt (or a regular mild steel bolt) is 
most certainly gonna wear an aluminum thread every time it is installed and 
tightened, not so much when it comes to a stainless steel thread.  Of 
course, an assembly lube should be utilized on the thread, both sides of the 
washer (if used), and contact areas under the bolt head.
Studs will always give a greater and more reliable clamping force over bolts 
and I believe that bolt (or to be a bit more correct - stud) stretch can be 
measured more effectively also.  I'm sure there are gadgets out there that 
will do both bolts and studs.
Finally, I referenced page 33 in the AMC POWER BOOK.  In my original post, I 
quoted what it said and it sure wasn't a whole heck of a lot!  This is the 
only reference I've found which mentions the procedure and I still don't 
understand what those "special bushings" are that the section talks about. 
Somebody has had to have done this procedure; I for one would welcome some 
more info on it before drilling my block.

Respectfully,
Bob Rapp
NN, VA
70 Machine