intake manifold help

[68GEETEE]

I have a vacuum leak where the intake manifold meets the head at the passenger side. When I reinstall the manifold, what is the correct torque specs for the bolts?? I have a 4 bbl edelbrock rpm performer aluminum manifold on a '68 302 motor. thanks.

 

[pabear89]

When you tightened down the bolts did you use a crossing pattern?
The wosrt thing you can do is snug one side up first.
It pushes the intake up slightly on the opposite side and will cause a leak.
I think the tork is 25-30 ft lbs?

PB

 

[68GEETEE]

I havent done the work yet, I want to know this so when i get into it later this week , i know what i need to do. I am doing the work at my car lot and dont have interent access there, so i need to know the torque sequence and specs beforehand, thanks


btw how sure are you about the torque numbers? I have an aluminum manifold, i would think they would be different from cast iron?

 

[pabear89]

Not sure on the #'s but when torking the manifold down,
start with the center and work out using a crisscrossing pattern.
I have found that by starting with just short of snug and work your way up to the required tork. It take a little longer by having to go over it a few extra times but I have had no leaks or warped manifolds using this system.

PB

Ps. When starting it's best to run the 2 center bolts evenly,
that way you pull the intake down straight and not having it walk up one side.

 

[67GTA-FB429]

Edlebrock should have sent you some info with the manifold, it will have torque specs and bolt order. My 429 was 25ft-lbs. According to Chilton, 22ft-lbs for a 302. Order is (looking at the front of the engine, pass side first: 5, 1, 9, 11, 3, 7 driver side: 6, 4, 12, 10, 2, 8). It should take you three times around to fully tighten them down. DO NOT over tighten or you will warp the manifold. Hope that helps.

 

[slapper]

If you use a few long studs to screw into the heads, and then lower the intake down on them, it can reduce the possibility of shifting the gaskets during assembly. Just something to consider.