barit 1 The reference to KC-135A having a somewhat greater theoretical fuel load than the KC-135E came from the Wikipedia page and is of no practical importance since the real-mission transfer fuel would be higher for the KC-135E
Boeing KC-135 Stratotanker - Wikipedia, the free encyclopedia
There is an interesting paper Air Force engineering paper on the ancient KC-135 ballast and tare weights which mentions a 'steel' and 'titanium' versions of the J-57 with a ~10% weight difference, (the latter going on the KC-135)
file:///C:/Documents%20and%20Settings/owner/My%20Documents/Downloads/ADA527036%20(1).pdf
Getting back to DC-8s, the early domestic DC-8-10 (EDITED) (J-57 powered) must have been a bit of a turkey and I think they were rebuilt with JT-3D fans?
EDIT...As tonytales corrects me next post it the DC-8-20 had JT-4 (J-75) engines (34 built, plus 15 conv. from -10). Of the 29 'domestic' DC-8-10 (J-57) the prototype N8008D was eventually re-engined with JT-3D fans and sold, of the 22 for United,by the mid-1960s 15 upgraded to -20 with JT-4 non-fan engines, 5 upgraded to -50 with JT-3D fans and 2 lost, all 6 built for Delta were upgraded to -50 with JT-3D fans (Source , the well-written Wiki page
http://en.wikipedia.org/wiki/Douglas_DC-8 ).
(For 707 detail variations I like the Airliner Cafe page
http://www.airlinercafe.com/page.php?id=72