engine swap
I have been down this road my signiture truck started life as a k3500 5.7 gas its now a tricked out 6.5 looks factory stock while except the after cooler remote mounted fsd the after market air cleaner, wiring wish can not tell it was not a 6.5 all its life if you like e-mail me privately i would be glad to talk to you on the phone to help answer your questions,
as for what you asked engine bolts directly in place no modifications, if you have auto you will need to swap out TC, yes you will nedd to find complete wiring harness unless you decided to go the mechanical DB2 fuel system route. not sure about ac mounting your a/c is on top of engine just like the 6.5 is radiator might work you will need to add a external oil cooler if you don't already have one.
I bought donor truck on e-bay for 2600 swap all part off of it on to this truck it had a vent oil pan where rods where hanging out.
e-mail be glad to help you all i can by the way where are you located
good luck
Greg
2003 CHEVY 4500 DURAMAX/ALLISON 14'
SERVICE CRANE BODY 16,500 LBS 14.5 MPG
1998 K3500 SRW CREW CAB TRANSPLANTED 6.5TD ELECTROINC INTO, HEATH COMPUTER, 40+HP INJECTORS, 4" EXHAUST, VACUUM ELEMTINATOR ON TURBO,UPGRADED COOLING WITH ALL GM PARTS,NO VACUUM PUMP, SST OIL COOLER LINES MADE LOCALY FRACTION OF THE COST, 3" TOURBO/BOOST GAUSGE ALL IN ONE, ADDED GEAR DRIVE GREAT HELP WITH STARTING TIME DOESN'T JUMP AROUND ANY MORE, INTERCOOLER 3" INLET AND OUTLET COOLER 12x24x4, ALSO ADDED MANDEL BENT CROSS OVER, HAD TRUCK REPAINTED AND OPUT ON ALUM FLAT BED