This was on Facebook.
This gentleman raced a big ford back in the Modified Production Days.
"Robert Eliezer
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Nice work. The issue with the pre-modern inline high performance six cylinder engines is always the same, especially with the “big block” 292 and 300s.
How do you feed a big block size cylinder volume with ports better suited to an early 265 Chevy V8 or Ford 260? The answer is always the same as well. You’ve got to keep the intake valve open as long as possible (duration) and as much as possible (lift) to allow the incoming fuel/air mixture to pack the cylinder as much as possible.
In our case with the 300 in 1975 it was an absurd Howard roller cam with 320 degrees of duration @ 0.020 lift (approx 285 @ “.050) and almost 0.0700 valve lift which was unheard of at the time even for the Pro Stock big blocks. It worked but at a cost. Valve spring technology was not up to the task and we broke at least one valve spring on every pass. And of course without the benefit of fluid harmonic balancers the 7,000 rpm operation and six cylinder 3rd harmonic vibrations would crack the forged cranks, both 292s and 300s, after 30-35 runs. It was just the cost of speed.
Later technology like the lump port heads for the 292s with 3 huge 2barrel carbs made by cut in half Holley Dominators allowed hp numbers over 600 while the 300s pretty much peaked around 500 with two ring pistons adding almost 30hp on our dyno and the second owner of our Maverick adding another 70hp with a billet crank featuring SBC size rod journals to further minimize parasitic friction losses. Our 2700# former H/MP car now runs routine 10.70s on the nostalgic circuit 53 years after brother Dick and I built it.
This cylinder head limitation is the same reason the Fords made quantum leaps in performance with the cut up and welded BOSS 302 cross flow hybrid heads and today with turbocharging.
Just thought a few of you inliners might enjoy a trip down memory lane. With my racing days long over my personal “special” ride for the last 43 years has been my 58 Chevy sedan with a tripower (3-1 barrels) 261 along with the usual headers, cam, posi, etc. Flawless operation for over 40,000 miles never touching a carb screw or having the distributor cap off the Mallory full centrifugal dual point. A bit of benign neglect there but it just works."

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Hyper_pak

Good styff Stan!

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Official Cookie and Mater Tormentor.

Thanks Killa Zilla

We seem to be at a standstill right now.

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Hyper_pak

I have a couple cams from Mike that are +.600". I also know he experimented with more but abandoned it.

There were some who did use more. Maybe Junior knows.

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Official Cookie and Mater Tormentor.

Tream Green Ran a skookum as frig cam

Check SSRN #28 for the oohey goohey detials.

Greg

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http://www.youtube.com/hyperpack

Tilley tried bigger cam lifts and they did not work well on the dyno. Long durations, yes, up to 270 or 275 @ 0.050".

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