Results with Box Upper on my 347 verses Cobra
I recently reported that I ran a 10.718 @ 123.02 mph with my 347 and Cobra intake. Shift points were approximately 5000 rpm. On another run shifting at 6000 my time dropped to 11.027 @ 120.01 mph.
Now I have installed a box upper. First run shifting at 6000 rpm, which compares to my 11.027 run, I ran a 10.657 @ 121.67 mph. All runs after this I lost traction so I have no times with shifting at 5000 rpm. Based on my dyno results with the box I feel my optimum shift rpm is about 5500. Unfortunately, I didn't get those results. I feel do have more et with the box by shifting at 5500. This 10.657 is a fair comparison to the Cobra as both were same shift points. That is a .37 gain with less peak hp on the dyno. This pretty much proves that hp/torque over the range is better than a higher peak hp/torque.
Now for the 1 3/4 long tubes. I'll report their results in a week or so hopefully.
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88 347, Twisted wedge heads,Comp Cams 224/230 cam, 1/4=10.718 @ 123.02 mph
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