I never heard of the Holley FlowMONSTER Brand. But I did just purchase a pair of FlowMASTER FLO-8430119 DeltaForce 10 Series Stainless on sale at Summit for $54.43 then take off 10% with coupon ... final price $49. Regular price was $140 each! The UltraFlow's were just too quiet. These ought to piss off the neighbors
Wait - I don't have any neighbors!