Intake & Exhaust Manifold Torque Specs

[Sam D.]

Can any one tell me what the torque specifications are for the bolts on the intake manifold and the exhaust manifold for a 1964 365 hp engine?

Thanks,

Sam

[Jack H.]

Re: Intake & Exhaust Manifold Torque Specs

Intake manifold: 25-35 ft-lbs
Exhaust manifold: 18-22 ft-lbs

[Sam D.]

Re: Intake & Exhaust Manifold Torque Specs

Thanks, what Manuel do you find that info in?

Sam

[Jack H.]

Re: Intake & Exhaust Manifold Torque Specs

The 1963 Corvette Shop Manual, Chapter 14, Specifications, Section, 6, Engine Torque Specifications table...

[Sam D.]

Re: Intake & Exhaust Manifold Torque Specs

I looked in the 64 shop manual and did not see any thing there!

Thanks,

Sam

[Jack H.]

Re: Intake & Exhaust Manifold Torque Specs

I don't believe there IS a 1964 (or 1965) shop manual...just supplement books providing information on things that changed for that model year from the basic 1963 issue of the book. So, if you've got a '64 or '65, you need the basic 1963 Shop Manual PLUS the 1964 or 1965 update/supplement book.

[Christopher R.]

Re: Intake & Exhaust Manifold Torque Specs

I'm not arguing with you. Just trying to understand something.

On the exhaust manifolds. 18-22 ft/lbs is just a little more than finger tight. OK, that's an exaggeration. But I'm trying to draw attention to a point. 18-22 ft/lbs isn't much. The bolt is 3/8" and can take lots more than that. The manifold is built like a brick outhouse. There's no gaskets on these manifolds. Where the manifold gets so hot, it must expand and contract a lot. In a previous life, I've installed these manifolds with lots more torque than that, and nothing happened.

Why so little torque? Wouldn't Chevrolet want to be sure these things sealed?

[Joe L.]

Re: Intake & Exhaust Manifold Torque Specs

chris-----

The 1969 small block specs that I have are 20 lb/ft for the end bolts and 30 lb/ft for the center bolts. However, it may have been different for earlier, with all the bolts spec'd at 20 lb/ft (i.e. 18-22 lb/ft).

In any event, we can only wonder why the specs were set as they were. But, the folks that set them knew a lot more about it than we do, so I don't get involved in second-guessing them. The use of the french locks on the end bolts is probably connected with the relatively low torque values specified.