a hot 440 and a mild 318 aint beans fer comparison.

his cam probably has some overlap, and the way cancelling mufflers work they dont cover all harmonics at all rpms.

if its that bad...seriously try minekie gold econo flo's(not a performann, but luxury) mufflers . i think they did a test and those beat all other econo SUV mufflers in sound. gabriels preimium and monroe hush-sonic had less reduction.

Y them off the collector and run 4.

my 323"(318) 4spd has 340hp cam, sp streetmiester 318 (idle-4500)intake, headers, 3.23 highway gear.

in order to quiet it, i used summit 19" glasspacks $12.99 after the collectors, and the then 19" summit $9.99 performance mufflers. no H or X.