Quote from dunc289
Jim, as you say, the K code numbers came from a different source, but this is where readers are looking to identify that " source ", so if you can post that source, or reputed source, it would be beneficial. Thanks. There may be more than one estimate from more than on source. Anyone? 

"The High Performance Mustang" by Tony Gregory, Fourth Edition, page three, second paragraph, first sentence. Take up any disputes with Tony.
The percentage figures are from "Mustang Does It" by Ray Miller, page 320. The same applies to Ray about disputes.
I suggest you buy both http://www.abebooks.com .
ISBN-13: 978-0-615-13362-1 or this forum for "The HP Mustang",
ISBN 0-913056-09 for "Mustang Does It".
Any other questions, see the Chaplain.
Jim