Hederics and co-driver John Williams led the auto section of the 5,500km event in their PWR Holden Rally Team Rodeo from the start in Kununurra nine days ago.
They covered the 1,998.15 competitive kilometres in a time of 16 hours, 10 minutes and 18 seconds.
Warrnambool driver Reg Owen and his co-driver Russell Cairns took second place in their Nissan Patrol, one hour 9 minutes 54 seconds behind the winner on a time of 17 hours 20 minutes and 12 seconds.
In third place, just five minutes 44 further back, was the Mitsubishi Triton of Penrith's Terry Denham.
Denham and his sons Michael and Warren had challenged Hederics for the lead throughout the first five days of the event, but lost all chance of victory when they broke a tail shaft on the sixth leg between Meekatharra and Leonora.
They made up 27 minutes on Owen and Cairns in the final three days, but could not quite bridge the gap to second place.
Hederics' record in Australian Safari is extraordinary. He won three consecutive events on the bike from 1990 to 1992, repeated the bike treble from 1994 to 1996, and has now won the auto section of the last three Safaris to be held, in 2003, 2004 and this year.
The first time is always the best time," the 44-year-old said.
“Having the lead, we didn’t really feel the pressure. But you never know, anything can happen."
“The pace at the start was the fastest I’ve ever done. We said 'one of us is going to break’, and the Denhams did."
“I'm relieved just to be here”
“It’s a mechanical car in an endurance event so anything can happen."
“Knowing every nut and bolt in your car and being fussy, as well as annoying your service crew, is all part of what you need to do to win."
“Determination and preparation are the main two things. And never give up."
Apart from a navigational error on Day three that cost him 18 minutes, Grabham delivered a superb performance in his debut Safari in the bikes section.
The 26-year-old Honda CRF 450X rider set the fastest time in 16 of the 33 stages, and was second in another nine.
He also rode the final six stages with a broken collarbone, sustained in a crash early on day 8 outside Kalgoorlie.
Grabham posted a total time of 15 hours 52 minutes and 12 seconds, 8 minutes and 53 seconds ahead of Condobolin 18-year-old Jacob Smith on his Yamaha WR450.
In third place, a further 20 minutes 39 seconds behind, was the KTM 660 Rallye of Adrian Channing, who had held the lead for three days in the early part of the event..
Channing, 38, from Broken Hill, finished on a total time of 16 hours 21 minutes and 44 seconds.
Grabham was a happy and relieved man after his victory.
“It’s more of a relief," he said. "The hard work has paid off. It's good to know everything has worked out."
"To have never competed in the event before and come out with a win, shows that anyone can have a go."
"When I came off and broke my collar bone I thought, oh God. But I thought, I can do it. I just kept on riding and I'm relieved to have made it here (the Perth finish line)."
“I went a decent speed for the first two sections today, then I eased off and let Jake (Jacob Smith) take it home."
Australian Safari Final Results (Provisional)
Top 10 bikes – After Stage 33 Day Nine (final stage/day)
1, B GRABHAM (NSW), Honda CRF 450X, 15:52:12
2, J SMITH (NSW), Yamaha WR450, 16:01:05
3, A CHANNING (NSW), KTM 660 Rallye, 16:21:44
4, A RIEMANN (SA), KTM 450EXC, 17:29:01
5, M FISH (VIC), KTM 525 EXC, 17:51:03
6, A COAKER (NSW), Honda CRF 450X, 17:52:36
7, D SCHWARZ (SA), KTM 660 Rally, 18:09:39
8, B KIENHUIS (VIC), Husaberg FE 650, 18:12:36
9, B HUDSON (QLD), KTM, 450 EXC, 18:18:42
10, T O'CONNOR (NSW), Yamaha WR410, 18:22:55
Australian Safari Final Results (Provisional)
Top 10 cars – After Stage 33 Day Nine (final stage/day)
1, HEDERICS/WILLIAMS (VIC), Holden Rodeo, 16:10:18
2, OWEN/CAIRNS (VIC), Nissan Patrol Y 61, 17:20:12
3, DENHAM/DENHAM (NSW), Mitsubishi Triton, 17:25:56
4, OLHOLM/GRIFFITHS (QLD), Mitsubishi Pajero, 17:53:04
5, OWEN/RYAN (VIC), Nissan GQ Patrol, 17:57:24
6, WALLENTHEIM/CARPENTER (SWE), Isuzu Vehi Cross, 18:19:59
7, WALTERS/SINCLAIR (NSW), Isuzu Rodeo, 18:20:43
8, DUNN/COVENTRY (SA), Toyota Landcruiser, 18:21:57
9, EMMINS/TJEPKEMA (WA), Nissan GQ Patrol, 18:27:31
10, MORALEE/FLOOD (WA), Toyota Prado GX, 18:39:03
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