I work on all sorts of machines with some of the biggest names in diesels around. All 3 of our service trucks(including an F-550 w/ 7.3) are diesel. The drillrigs I work on have either Caterpillar, Duetz, or Cummins engines. And then we have vibratory & percussion hammers used to drive sheet or woodpiles with either Cat, John Deere, or Cummins diesels. We use different namebrands of hammers that come from France, England, & of course, USA. The American hammers we use are strictly Cat, & range anywhere from a simple turbo L6, to a twin-turbo V10. One particular hammer we use, which is the smallest, uses a Cat 3208 & is the only one out of the smaller hammers that is an N/A V8. The other day, when we were out in the yard testing it, I listened to the engine idle. I swear, it has an uncanny sound to that of a Navistar IDI. @ full throttle(2500rpm) it sounds even more like the old Navistars. The way it starts also sounds similar, except for the fact the Cat powerpack uses a starting switch called a 'key' & a Murphy button. & finally, the displacement is virtually the same. Is there a connection? Did Cat have a hand in the design of the old Navistar 7.3, or vice-versa? Did one steal the design from the other? Or does it just so happen a Cat 3208 sounds exactly like an International Navistar 7.3? I swear, if you were blindfolded in front of these 2 engines, you would NOT be able to tell the difference when they are running. They're like identical twins!