Indy heads versus X Heads

340, you're right. And the technology for iron heads was perfected in the 70s and the parts that best match are heavy heavy in comparison, domed hurting flame propogation, and simply don't make use of a lot of knowledge gained since then. I'm sure you already know that tho :D.

As far as what kind of engine I might spec them for... I dont think anything with a factory stroke and going in a street car and has a realistic budget really needs them. $3500 plus special headers I think is a little much for a top end. They have more room to grow than RPMs, but RPMs with a good CNC job are a tad less coin, use standard headers, and will out flow more than as-cast oval -1s with only a slightly larger port volume. Also, I don't like the 2.10 intakes. IMO they are just too large for every bore size in std blocks and are even shrouded when the bores are notched. With a 4" or longer stroke engine, they offer a great package with growth room RPMs simply can't.