this is some pretty amazing stuff , click on the link , then the picture at the bottom with Jay Leno in it , then the one with Jay Leno again https://www.nextengine.com/indexSecure.htm
here is some good info for you , scroll down toward the bottom and read "pressure radiators" and then further down "radiator caps". http://www.flatheadv8.org/rumblest/cooling.pdf ......... heres another link you might like Rev.http://bham.craigslist.org/cto/1002602161.html