I recently acquired a NOS 421 Super Duty cam and thought I'd share a few pictures of this piece of Pontiac racing history. Pontiac part number 541596, made by the Melling Tool Company who was the OEM supplier for all of the Pontiac cams under part number RPC-2. This is a flat-tappet solid-lifter cam known as the 'McKellar #10 cam', named after Pontiac engineer Malcolm 'Mac' McKellar who was their camshaft designer during those glory days. The valve timing specs are pretty much identical to the later computer-designed '69 -'70 370-HP 400 Ram Air IV 9794041 hydraulic lifter cam. Both cams had 308 degrees intake/320 degrees exhaust of advertised duration. However the McKellar #10 cam had lower valve lift values of .445" intake and .447" exhaust compared to the RAIV cam with .517" of valve lift. Both cams used stamped-steel 1.65:1 rocker arms. The dual-quad Carter AFB-equipped 12:1 compression 421 SD engines running this cam were rated at 405 HP, but they were probably making closer to 500 HP. Old-time factory racing camshaft technology at its best, Pontiac was really on their game back in the early '60s. Here are a few pictures of the long-duration low-lift cam lobes, first 2 pictures are the intake lobes. Exhaust lobes.
Pontiacs of that era were just so cool, and you are right, they were on top of their game back then. I had two 66 GTO's, one tripower and one four barrel, plus a 63 Bonneville 389 that I put a 421 cam and trips on. That big old Bonneville would haul and surprised a few vettes and 327 Chevies. I still have a soft spot in my heart for Ponchos. Don
When pontiac was fully behind factory racing, nobody could catch them. Thanks Bunky! Wangers explained, “Bunky Knudsen took over the Pontiac division in 1956 and made up his mind to go racing. He picked out members from his engineering group to create the Super Duty Group, and they created the Super Duty Engine. In 1957 the AMA Automobile Manufacturers Association formed a gentleman’s agreement to back out of organized auto racing and motor sports of any kind.” “The AMA was not pleased to be led around by the nose and throwing money at hillbillies trying to help them beat each other on their own race tracks! Bunky had other ideas, though. ‘To hell with those guys,’ Bunky said in reference to the AMA agreement. ‘I’ve got a division to save and we’re going racing.’ The rest of the automakers went to sleep, and Pontiac went racing full force. The Super Duty group went to work making more horsepower than ever with regular Pontiac engines and started to win on the racetrack. By 1961 Pontiac was dominating absolutely everything.”
Holy shit!!!!!!! Those intake lobes are flat on top! Lotsa duration there. My 370 came to me [unclaimed at machine shop] with a #6 cam but it's not near as radical looking as that #10. I used a lunati grind in my 370 and saved the milder #6 cam for later.
hey Rocky, did you ever fire off that 370 ? I've got a few of those engines...never saw a 370 I didn't want to get and buy...
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