Acoupla questions

[cb ndrhsr]

Greetings folks, I have 2 questions to ask. 1st: why are the exhaust manifold bolts different sizes on my 8ba? The front ports are 7/16", the middle & rear are 3/8". Got to be a reason for this. 2nd: how will a 3" extension affect torque readings on my torque wrench, some bolts just need and extension to get to. Thanks. CBN

 

[Bob G/Spanaway]

Dunno why the bolts are different.
Extension won't change anything.

 

[georgewarren]

I think the center bolts act as locators, while the outer bolts allow for heat expansion of the manifolds.

 

[ken ct]

All flatheads are like that.They came from the factory like that. ken ct.

 

[BrianCT]

Probably goes back to the original 21 stud design where the head pipes also mount on the front studs.

 

[Walt Dupont--Me.]

Probably goes back to the original 21 stud design where the head pipes also mount on the front studs.

Brian CO has it right. Walt

 

[cb ndrhsr]

Thanks for the answers, I knew they were like that, I just didn't know why.