The YF-17 did indeed look a lot like the F-18, and for good reason.  At the time that the US Air Force was shoping for the F-16, the US Navy was also shopping for a multirole fighter that was lighter and less expensive than the F-14.  When they saw the YF-17, they really liked it, but it was not carrier capable.  So when the YF-17 lost, the Navy approached Northrop and asked them to produce a fighter that was carrier capable and twin engined, based on the F-17.  Northrop obliged, and the rest, as they say, is history. The new plane was significantly larger and heavier, with the very beefy landing gear that carrier landings require, as well as the reinforced frame.  The extra weight also meant larger fuel tanks, so the new fighter really was a different plane. 
The twin engines are another reason that the plane is popular with other users.  Canada and Australia both specified twin engines because their fighters routinely have to cross regions that are incredibly remote.  The reliablility of the twin engines was the deciding factor in rewarding the contract to McDonnel Douglas. (then Northrop)
YF-17 Specs
Manufacturer:	Northrop Corporation, Aircraft Division, Hawthorne, California	
Number Built:	Two: Prototype #1 (s/n 201569)	
Wing Span:	35 feet	
Overall Length:	55 feet, 6 inches	
Overall Height:	14 feet, 6 inches	
Wing Area:	350 sq. feet	
Clean Takeoff Weight:	23,000 lbs.	
Maximum Takeoff Weight:	30,630 lbs.	
Speed (Maximum):	Mach 1.95	
Speed (Cruising): 	Mach 0.85	
Ferry Range (W/Tanks):	2,800 miles	
Service Ceiling:	60,000 feet	
Powerplants:	(2) GE YJ101 Turbojets rated at 15,000-lb thrust.(Note: The YJ101 was the prototype to the F404 engine installed in the McDonnell Douglas / Northrop F/A-18 "Hornet" carrier based fighter.	
Armament:	(1) 20-mm Gatling gun (2) Wing tip IR missiles (4) Pylon stations for stores
F/A-18 A	                                                           F/A-18 C	                                  F/A-18 E	
Country of Origin:	USA	                                          USA	                                          USA	
Manufacturer:	McDonnell Douglas Co., Northrop	McDonnell Douglas Co., Northrop	McDonnell Douglas Corporation	
Designation:    	F-18	                                          F-18	                                          F-18	
Version:	        A	                                          C	                                          E	
Nickname:	        Hornet	                                  Hornet	                                  Super Hornet	
Type:	                Carrier-Based multirole Fighter	        Carrier-Based multirole Fighter	         Carrier-Based multirole Fighter	
Crew:	                1 Pilot 	                                  1 Pilot 	                                 1 Pilot 	
First flight:	       18 November 1978	                         September 1987	                         December 1995	
Inventory:	       371	                                          622	                                          future production	
Unit prise:	       $ million	                                  $24 million	                                  $35 million	
Performance
Ceiling: normal	n.a.	                                           n.a.	                                           13 865 m / 45 490 ft	
maximum	        15 250 m / 50 000 ft	                  15 250 m / 50 000 ft	                 15 250 m / 50 000 ft	
Combat Radius:	750 - 1000 km / 466 - 621 miles	750 - 1000 km / 466 - 621 miles	856 km / 532 miles	
Flight Radius:	without refueling	
                         2 130 km / 1 323 miles	                  2 130 km / 1 323 miles	                  n.a.	
with refueling	3 700 km / 2 300 miles	                  3 700 km / 2 300 miles	                  n.a.	
Take-off distance:	n.a.	                                          427 m / 1401 ft	                          n.a.	
Landing distance:	n.a.	                                          n.a.	                                            n.a.	
Landing speed:	248 kmh / 154 mph	                 248 kmh / 154 mph	                   n.a.	
Designed g limits:	+7.5g 	                                  +9g 	                                           +7.5g	
Weights				
Empty:	         10 455 kg / 23 050 lb	                 10 886 kg / 24 000 lb	                 13 336 kg / 29 400 lb	
Normal takeoff:	16 220 kg / 35 760 lb	                  16 651 kg / 36 710 lb	                 n.a.	
Maximum takeoff:	22 317 kg / 49 200 lb	                  25 400 kg / 51 900 lb	                 29 932  kg / 66 000 lb	
Max payload:	11 862 kg / 26 150 lb	                  14 514 kg / 32 000 lb	                 8 050 kg / 17 750 lb	
Dimensions	 			
Span:	                 12.33 m / 40ft 5in	                          12.33 m / 40ft 5in	                          13.65 m / 44ft 9in	
Lenght:	         17.08 m / 56ft	                          17.08 m / 56ft	                          18.38 m / 60ft 3in	
Height:	         4.68 m / 15ft 4in	                          4.68 m / 15ft 4in	                          4.88 m / 16ft	
Wing area:	         37.16 sq m / 400 sq ft	                  37.16 sq m / 400 sq ft	                  46.45 sq m / 500 sq ft	
Speed				
Max speed:	at H=0 m	
                         1 100 kmh / 683 mph / mach 0.93	1 100 kmh / 683 mph / mach 0.93	n.a.	
at H=11 000 m	
              1 915 kmh / 1189 mph / mach 1.6 class	         1 915 kmh / 1189 mph / mach 1.6 class	 mach 1.8 class	
Cruising speed:	
                      1 060 kmh / 658 mph / mach 0.89	         1 060 kmh / 658 mph / mach 0.89	 n.a.	
Propulsion				
Powerplant:	General Electric F404-GE-400 Turbofans	General Electric F404-GE-402 Turbofans	General Electric F414-GE-400 Turbofans	
Thrust:	normal	n.a.	                                   n.a.	                                              n.a.	
with afterburner	71.2 kN / 7 258 kgf	                  78.7 kN / 8 022 kgf	                     98 kN / 10 027 kgf	
Number of engines:	2	                                   2	                                               2	
Weapon systems
Primary:	General Electric 20mm M61A1 Vulcan cannon 570 rounds	
                                                                             General Electric 20mm M61A1 Vulcan cannon 570 rounds	
                                                                                                                                General Electric 20mm M61A1 Vulcan cannon	
Air-to-air:	AIM-120 AMRAAM, AIM-7 Sparrow and/or AIM-9 Sidewinder	AIM-120 AMRAAM, AIM-7 Sparrow and/or AIM-9 Sidewinder	AIM-120 AMRAAM, AIM-7 Sparrow and/or AIM-9 Sidewinder	
Air-to-ground:	Conventional, JSOW, JDAM,  Rockets,AGM-45 Shrike, AGM-65 Maverick ,AGM-84 Harpoon , AGM-88 HARM , B61 tactical nuclear bomb	Conventional, JSOW, JDAM,  Rockets,AGM-45 Shrike, AGM-65 Maverick ,AGM-84 Harpoon , AGM-88 HARM , B61 tactical nuclear bomb	Conventional, JSOW, JDAM,  Rockets,AGM-45 Shrike, AGM-65 Maverick ,AGM-84 Harpoon , AGM-88 HARM , B61 tactical nuclear bomb	
Other:	Electronic Counter Measures and targeting pods	Electronic Counter Measures and targeting pods	Electronic Counter Measures and targeting pods	
Fire points:	9	9	11
I did try to edit the info into columns, but it did not work.  For more info, see these links.
http://www.wmof.com/yf17.htm                     http://www.fortunecity.com/tatooine/leguin/643/web_tree/F-18/html/txt_f18specs.html#
Dean.