whistling question

Moper: engine specs in previous post, but here they are again:

1971 383 Magnum
Stock pistons as far as I know
452 Heads "fully" ported as told by previous owner. Milled 0.060
Compression: I was told by prev. owner 9:1
Comp XE 268 hydraulic cam
Distributor is a Mopar Performance one. NOT an MSD distributor. It is, however, hooked to an MSD 6 box.
Demon 650 Vac Sec carb.
Holley Street Dom. manifold
Long tube headers.