Okay, I've got the data from the stories all mushed together and I have to say, looking at it graphically, the results aren't exactly what I would have suspected and could squash some long held notions of what performs well or not and what impact some basic engine specs can do to performance. I'm looking forward to feedback from our more knowledgeable engine builders here.
So, the basics for those who haven't read the articles. Test was performed in two parts. Part one was a basic performance type rebuild with a performance cam, decent compression, and some factory iron heads. It was the basic kind of refresh most people do for your general muscle car type build with a few internal tricks and premium parts. Part two consisted of the same short block getting a larger cam and a set of Edelbrock RPM aluminum heads. Since we have two differing engine configurations, you might think it invalidates the test. However, they did use three manifold combos on both engines configurations so you can get a direct comparison of what exactly a head and cam change can do for an average build up. These would be the M1 single plane and the OEM styled six-pak.
First up is the peak performance numbers since this seems to be the most popular way for us to compare power. Graph is attached for review, so please open it up and take a gander.
The typical stuff; Torque for the dual planes all tend to occur pretty low, hanging around the 3900 rpm range for peak, while single planes peak around 5000 for a 1600+ rpm spread from highest to lowest. Values for lowest torque was 431#, highest was 494#. That is only 63 lb ft of difference.
Horsepower actually tightens things up a bit. The rpm spread from highest to lowest is no more than a 700 rpm regardless of intake, cam, or heads. Lowest horsepower was 412, highest was 540, a 128 horse difference.
