Nebraska test will show that tractors of that era will produce about 15 H P hrs per gal.doing drawbar work. That is to say a 7140 w/200 rated HP would burn 13.3Gal per hr.(200/15 =13.3)  Likewise a 7150 at 215 rated HP would burn 14.3 GPH. So then the numbers would justify 1 GPH increase.

However it has been well established that many 7150's might be turning 250 + from the factory. That would be 16.6 GPH (250/15=16.6).

Soooo.............If a 7150 was turned up and a 7140 was set near factory rating the 7150 could easily burn 2.5 more GPH.

If the 7150 is set to specs and it shouldn't burn appreciably more fuel than a 7140 that was set to factory spec. since they are basically the same tractor anyway.

Clear as mud? Have a good night,

John