Who is your target audience? If they did this mod wouldn't they be doing cam intake headers too? So why limit yourself to the stock parts and design and mildly improve the exisiting head rather than stepping up to full cross flow? Sell an integrated Package (like Edel* and Holl* do).
Crossflow, use LS valves, chamber shape, and rockers. Why reinvent the best flowing out of the box stuff? Think about the performance out of a stone stock 5.3, without going over 6000 RPM. For a more torque lower RPM alternative look at Vortec port and chamber (best torque curve SBC head.
Design for different pistons, raise the CR well over 9 with an aluminum head and modern chamber (how lean can a 5.3 run?). There are forged 3.9** LS1 pistons with minimum dish and and standard pin size. Or somebody make a realistically priced true flat top for the 250.
The cam shaft package limits lift, so the high ratio rocker is needed.
Intake positoned to clear stock 250 bore, exhaust where you can get it.
Ditch the factory intake/exhaust, if I'm gonna spend $1000 on a head upgrade then the intake is getting upgraded anyway. Look at how simple the intake is on a 5.3. Or a vortec. New intake should be common plenum (for the carb guys), fully divided at the ports for injectors, and come with injector and nitrous bosses. Think about the LS engines and the carb conversion packages.
Anyways, that my nickel. Not sure I fit your profile as I no longer use the 250's as my DD (get better fuel economy out of my 6.2l diesel's). But that's the stuff I was looking at when my next build was going to be a 250.
Last edited by D13; 02/16/11 12:55 PM.
