you need 1203's with vortecs when the lower intake is converted
I had a set of aluminum "gaskets" (shims really...) made to make up the difference... about 3/16th thick, use 1203's on the head side and silicone on the intake side... I did not have to have modify my lower beyond opening up the intake ports....Re: 18 degree gaskets on Votecs ?
The 1203's are too thin for my set up. The intake has been cut several times and now sits abit low on the heads. I had to longate the bolt holes for them to line up with the holes in the heads. This maybe why its not sealing the botom of water holes, and leaking into oil.
If 18 degree gaskets line up with the Vortecs, i can then order thicker ones.
FELPRO does not make thicker 1203 gaskets.