AIR TAXI CARGO FLT CLBS ABOVE ASSIGNED ALT. CONFLICT WITH MLG.

Narrative

AFTER DEPARTING SLC RWY 16R I WAS TOLD TO SWITCH TO DEP FREQ 135.5 AND A R TURN HDG 280 DEG. I CONTACTED DEP CLBING THROUGH 6200 FOR 8000. THE CTLR RESPONDED FOR ME TO MAINTAIN 8000; AND I RESPONDED 'ROGER 8000.' APPROX 30-45 SECONDS LATER THE CTLR ADVISED ME OF TFC; AN MLG NEBOUND AT MY 10 O'CLOCK DSNDING OUT OF 11000 FOR 9000. I RESPONDED 'TFC NE IN SIGHT.' IN THE PROCESS OF LOOKING FOR THE TFC AND SCANNING FOR ADDITIONAL TFC I SCANNED MY PANEL AND NOTICED THE ALTIMETER GOING THROUGH 8400. I IMMEDIATELY PUSHED THE NOSE OF THE ACFT DOWN AND PROCEEDED BACK TO 8000 JUST AS THE CTLR ADVISED ME I WAS ASSIGNED 8000 AND TO DSND IMMEDIATELY TO 8000; TFC WAS DSNDING TO 9000. I RESPONDED 'ROGER; I HAVE VISUAL SEPARATION WITH THE TFC;' AND LEVELED AT 8000. I WAS OFF MY ALT FOR ONLY A FEW SECONDS AND NO EVASIVE ACTION WAS NECESSARY. I HAD THE MLG IN SIGHT; BUT HE WAS ON A DIFFERENT FREQ SO I DON'T KNOW IF HE SAW ME; WAS ADVISED OF MY POS OR FELT I WAS A HAZARD. I ESTIMATE THE TFC PASSED ABOVE AND BEHIND MY POS BY 1-2 MI. BEFORE HANDING ME OFF THE CTLR ASKED ME WHAT MY CLRNC HAD BEEN AND I RESPONDED '8000 FT.' I REALIZED MY MISTAKE IMMEDIATELY AND TOOK PROMPT ACTION TO GET BACK TO MY ASSIGNED ALT.