I have a 99 Volvo Penta SBC and need a set of manifolds and risers. I have a good deal lined up for some new GLM mercruiser manifolds and like new mercruiser stainless risers. Can I use them on my VP? Anyone have any thoughts on the mercruiser stainless srisers? Any issues with them being used ona cast iron manifold? I use the boat 90% in salt water. Thanks.