If I use either the 750 3310 Holley or a 750 dp do I need to use a pressure regulator? I am using a carter mech. pump. This is for a street 406sbc

Thanks

If the pump is putting out 5-6 psi consistently at all engine speeds you are okay without a regulator, but to depend on that being true is not a good idea. A standard dead-head style holley regulator should work just fine for your application. A fuel pressure guage is always a good idea. At least use one to check the fuel pressure to set the regulator. I also reccomend using a fuel filter between the pump and the regulator, a good filter with cylindrical pleated paper element. A proper filter and regulator will eliminate most of the problems that can occur with any carburetor.