i just took off my old stock intake manifold and 2bbl carb and put on a dual plane wiand x-celerator intake manifold with a edelbrock 650 cfm 4bbl carb... it started up and ran strong but when i put coolant in it and it hit a certain level it started leaking from one of the heads...could this be because i might have not put enough silicone around the intake gaskets?

 

I'd guess that maybe you put too much on, or let it dry too long before torqueing the intake, or maybe even overtorqued the intake. You only need a very thin smear of silicone around thecoolantports on the intake gasket. Lay down the front and rear silicone beads first, then smear some silicone around the coolant ports on the gaskets, than immediately drop them into place and torque the intake down to about 20ft-lbs.