Hello Everyone: I'm the new rookie on the block Hopefully someone out there can help me out here. Just dropped a 383 stroker in my 73 corvette. Everything is new except I went cheap and used the old weiand spreadbore intake I had on my old motor. Well I have 100 miles on this motor and noticed that in the front of the intake on both sides of the motor looks like water is starting to seep out between the intake and the aluminum heads. Pretty bummed. Also noticed that the bolts have somewhat loosened up so I retorqued all the bolts on the intake to 25 lbs. Could this be happening because (A) the bolts loosed up? or (B) maybe I should have had the intake machined. What do you guys think? Thank you in advance for your help. Charles

 

In my experience I have always used a tap and cleaned the threads out on the cylinder heads to make sure their clean and dirt free. And I always use 'New" bolts to tighten down the intake manifold. Also, did you coat the intake and cylinder head water jackets gaskets ? and I also always coat the intake bolts with non-hardening 'loctite' sealant to insure the bolts don't leak. for example, the bolts on cylinder 7 go directly into a water gallery, so they will leak if not coated with sealant.

The intake 'May' not be perfectly flat, so It would of been wise to have it's ports to cylinder head mating surfaces trued by a machine shop, but at this point your going to have to drain the cooling system and I would buy a more effective manifold and then do the sealant of the intakes gaskets & bolts. Sorry I couldn't of more help.

 

apply a small amount of silicone on both sides of the intake gasket at the water passages. be aware that water could also be leaking on the other side into the oil. the first sign of that will be a white foam on the inside of the valve covers.

 

Unless your head manufacturer recommend something different, the Fel-Pro blue intake gaskets are good ones to use, and put absolutely NO sealant of any type on the gasket surfaces. DO NOT use the supplied rubber end valley gaskets either, as they could be preventing the intake manifold from torquing down to where it wants to be. Instead, put down a 1/4" bead of RTV (Ultra Black) on the tops of the valley walls, and run it up onto the tab of the intake gaskets. Be sure to set the intake manifold down straight and even.
If the new heads have been shaved, or the block was decked (and the old ones weren't) that can cause a mismatch between the heads and the unshaven intake manifold because the width and angles between the heads then gets narrowed and changed.
And yes, it's normal for the intake bolts to need to be retorqued after the first heat and cool cycle, and checked periodically after that. They didn't "loosen", everything just settled into place. If you didn't check or retorque the bolts at all, you may have caused your own leak.