Detroit 60 series 14 litre

Have had my dd15 560hp on the dyno, 425rwhp, seems low to me for being a 560. 500hp ISX seems to do a better job.

 

that is low..my 560 dyno at 460 and i think that is low.....my 500 1650 s 60 dyno at 430 . i figure this darn new 560 should at least put 490 to the ground but now they say 80% of h.p. is within spec.........last 30 yrs seemed 85% was the norm......

 

I actually have a 2000' series 60 14 liter at 575 hp and it really pulls like it's got hp to spare. Last truck was 12.7 liter at 500hp which pulled good but not like this one. Not very mountains that pulls below 55 mph grossing 80,000.
I'd think something wrong with your 14 liter if it isn't pulling like crazy.

 

I drive a 2000 century and is doing 6.78 mpg at 70 mph

 

Good