In the breakaway with Morton, David Lopez (Sky), Nicholas Edet (Cofidis) and teammate Rob Britton, Huffman perfectly timed his run into the finish to out sprint Lopez and Edet over the line.
It was Huffman's second victory at this year's race after a surprise win on stage 4 in Santa Clarita, again from the break.
The quintet only managed to break free after 40 kilometres raced as the sprinters' teams craved a bunch finish in Pasadena. But the second climb of the day up the Angeles Forest Highway was enough for the leaders to build a one minute and 35 second advantage.
After the Upper Big Tujunga Canyon climb, the escapees still held a lead of around a minute. On this climb a frisky Andrew Talansky (Cannondale-Drapac) and Sam Oomen (Sunweb) back in the bunch both tried their luck, but Majka and Bennett quickly responded.
Despite never looking troubled, the Kiwi said he still felt under pressure.
"It was a pretty hectic day," he said. "We thought we had it under control early on and then it just kicked off.
"We spent a hundred kilometres pushing pretty hard and to get under the 3 kilometre banner, it was a big sigh of relief.
"I was under pressure a little bit there but the team was just awesome today."
Huffman also scooped up all the major KOM points on offer but despite finishing the stage on equal footing with KOM leader Daniel Jaramillo (United Healthcare), he was edged out of the competition on count back.
Australia's Morton worked hard all stage to shake off stage 6's horror time trial and take back the young rider's classification, the final home for the jersey atop his young shoulders. The break's final advantage of 22 seconds over the bunch sealed the deal for Morton over Sky's Tao Geoghegan Hart.