Dd 53
Welcome to the DieselPage,
I have rebuilt many 53, 71 & 92 series DD motors and I have never seen an inline DD desined to lay on it's side. Look at the direction the oil dipstick points and that will tell you which way is down on the motor. There should be a long build sheet (metal) tag on the valve cover. That tag will tell you all about the motor. Additionally, if it was a military motor it could have a 24 volt starter. You have a good uncomplicated motor that is easy to maintain and will run forever. Books for a DD-53 should be pretty much the same for all of them.
Good luck
John
*2006 Chevy, 3500, 4X4, DRW, (LBZ) D/A, CC, LT, 252K Miles, 19.5" Wheels, Mag Hytec Transmission Pan and Differential Cover, SS Grill Guard, Racor 2 micron aux fuel filter, 100 Gallon Aux Fuel Tank, using Edge Evolution, Predator Diablosport, Kennedy ECM tune, Fitch Fuel Catalyst.
*2006 Four Winds, Dutchman, 36', RV, D/A, 5500 Kodiak.
*1993 Harley Davidson, Turbo charged, Springer Softail.
*2007 Pontiac Solstice.
*2005 Jeep, Liberty, CRD (diesel).
*Full-timing in USA, see America first.
BUY AMERICAN or CANADIAN, NOTHING from CHINA .