After my 50's carbs fail I'm wondering if any Y-Blocker have tried a 090470 Holley 470 CFM Truck Avenger off road. They claim it is for 300" engine which won't see over 4500 rpm. I'm not looking to tip one 40 degrees so that claim doesn't mean much. A 390 cfm sound too small even tho I would like the small primaries for milage. Stock jetting for the Truck Avenger is 57 with a 25 power valve. The 390 is 51's with a 65 PV. Looks like both would be pretty economical. Thanx ...JD