273 commando HELP!!!

As far as the 273 goes you'll want to go with a good intake if possible D4B and a good Carter around 625 cfm. Go with the Hipo exhaust but skip the muffler and run just the resonator. Accurate Limited has an enhanced single exhaust kit. You should have the good closed chamber heads so don't go too crazy on the cam. Try and find a cam that compliments the flow of the heads. You may even consider going with a larger valve. PM me and I can give you more specifics.