351W stock intake question... helP?

[xoxbxfx]

Well, I have NEVER run into something like this. I have an early 69 351w 2v intake manifold. Got it bolted down and everything and I started to fill the coolant into the radiator then 4 holes in the intake started leaking. They are about 1" in from each corner just inisde of the corner intke manifold bolt holes. Anyone know what on earth they are for and how to fix the problem?? They are not tapped, no holes in the heads for it, and Im stumped.

Thanks
Tim

 

[Red Barchetta]

What kind of heads are you running? If you have aftermarket heads, they probably only have 12 bolt holes, 4 have been eliminated where the water passages are. I'm runing some World Products heads on my 351W with an old-school Offenhauser dual port intake manifold that has the 16 bolt holes. I ended up just tapping the holes and plugging them with bolts coated in Permatex Aviation Form-A-Gasket and never had a leak.

 

[bnickel]

yeah, after 76 i think Ford started using the 12 bolt intakes instead of the early 16 bolt intakes. you might be fine just filling the bolt holes on the intake with silicone, if you don't want it to look ugly you could cut the extra intake bolts off just below the head of the bolt and silicone that in as well.

 

[69Rcode_Mach1]

Did you run a layer of RTV around the ports between the gaskets and mating surfaces?

 

[xoxbxfx]

Did you run a layer of RTV around the ports between the gaskets and mating surfaces?

nope... Im sorta wonding if the moron at Autozone gave me the wront intake gaskets but I really dont want to pull the intake just to buy new gaskets. Im gonna check the casting numbers on the heads but I believe they are stock 69 351w heads

 

[69Rcode_Mach1]

nope... Im sorta wonding if the moron at Autozone gave me the wront intake gaskets but I really dont want to pull the intake just to buy new gaskets. Im gonna check the casting numbers on the heads but I believe they are stock 69 351w heads

There's your problem, you need to pull the intake off, and put a thin bead of RTV around the coolant passages on the intake and cylinder head side, then tighten it down. This will seal the coolant and keep it from wandering.

 

[xoxbxfx]

There's your problem, you need to pull the intake off, and put a thin bead of RTV around the coolant passages on the intake and cylinder head side, then tighten it down. This will seal the coolant and keep it from wandering.

call me crazy but the last 5-6 motors we ahve put together we have never done that.

 

[69Rcode_Mach1]

It is good practice and necessary, I am surprised coolant has not leaked out and opened up a vacuum leak. If anything give it a shot and see what if there is no RTV on it. Might I also recommend putting a thick layer of RTV on the ends of the Intake instead of using cork end gaskets.

 

[xoxbxfx]

It is good practice and necessary, I am surprised coolant has not leaked out and opened up a vacuum leak. If anything give it a shot and see what if there is no RTV on it. Might I also recommend putting a thick layer of RTV on the ends of the Intake instead of using cork end gaskets.

lol..i dont use the cork gaskets