First let me start off with (I AM NOT WANTING A FREE PROM) I am building a 350 HSR engine for my vert that will be a 9.5 or 10.0 compression cruiser engine that needs to get around 25MPG and idle well. If anyone has done a mild 350-400HP (flywheel) engine that idles well and still runs good then I need advice. The engine will be going in my vert which will not be raced but daily driven. It is a 350 bored 40 with a factory 1pc steel crank, 6 H beam rods and Mahle forged pistons. The HSR flows about 275 out of the box so I am guessing I need heads that flow about the same and a ZZ4 cam or maybe a 268 cam I have heard some speak well about. If someone has built and tuned an engine similar please let me know what you used since I am ready to purchase heads and cam and get the motor installed in my vert.