I have a set of the Larry Smith ported TrickFlow 270's and they are part of a great build but I used them on my 526". They flow 378@.700 and work really well with the cubes to get me a bunch of power but not have to spin the snot out of it. If I were doing a standard stroke 440, I would probably do the 240's instead. If you get them ported by Larry Smith he has been getting 360'ish CFM porting them with only a port size in the 250 range. This would make a great street head with some serious potential for horsepower with a higher velocity port with the smaller cubes to keep it nice and snappy. I used to have a set of standard port Stage VI's that were ported and flowed in the 335cfm range and were outstanding for this same reason. This route would probably be great for anything up to 500" and then you would probably want to start thinking about the 270's so you don't start choking the motor. If you know you are going to go bigger than 500" some day, then maybe go with the 270's but plan on building it to rpm a little higher and use some 4.30's or so to not have the big port hamper you.
