I've seen the numbers Larry gets when he ports both 240's and 270's as well as what stock 270's flow. Best bang for the buck is the 240's ported. The ported 240's will flow more than the stock 270's and be better suited for a 470. If you are stroking to a 511 it will probably be a coin toss. Bigger than that and the 270's leave you room for picking up a little more later should you want to go that route. I was one of the first sets of 270's Larry did and got some great numbers out of them (
[email protected]). If I hadn't got my 270's for the price of the 240's, I would have gone the 240 route. I say this because the bigger ports are a little softer down low for all the street driving my car sees. Not horrible but not a snappy as my old stage 6's were.