Here some for you:
"The combat models
The first combat model was the Ju 290A-2. This was basically a Ju 290A-1 with FuG 200 Hohentwiel search radar. The Hohentwiel radar could detect a convoy at a distance of about 100km. The Trapoklappe was retained. The Ju 290A-3 was almost identical, but had a Focke-Wulf gun turret with a lower profile. The A-4 model had an additional dorsal gun turret, further aft. On 15 October 1943 Fernaufklaringsgruppe 5 (FAGr.5) began operations from Mont-de-Marsan, in France. They replaced the Fw 200C in its role of gatherer of information for the U-boats. After two A-2s, three A-3s, and five A-4s, it received the first A-5.
The A-5 was a fully operational combat aircraft, and appeared in the spring of 1944. It had protected fuel tanks, armour plating for the crew positions, and redesigned beam gun positions. Also, all but one of the 13mm MG131 guns were replaced by 15mm MG151 cannon, with a difference in firepower much larger than the small increase in calibre suggests. The crew was increased for seven to nine. The Ju 290A-5 was well armed, could absorb damage and did not have the structural weaknesses of the Fw 200C. This was a good replacement for the Condor, but only 11 were completed.
And three Ju 290A-5s were retracted from FAGr.5 after delivery. All their armament was removed, and additional fuel tanks installed. They made a non-stop trip to Manchuria, and a similar flight back, to exchange documents and strategic materials with the Japanese. After the loss of the Atlantic coast, the Ju 290s were all used as transports. Some went to the famous KG200, that seems to have used the bombers to drop agents and supplies behind the Allied lines.
The single A-6 was built as a personal transport for Hitler, originally with a pressure cabin but later this was abandoned and a 40-seat interior was installed. In April 1945 it flew to Spain, where it was used for some years.
Despite an order for 25 of them, Junkers completed only a few A-7s, which had an additional MG151 in a bulbous, glazed nose and was equipped to carry guided weapons. The A-8 had again increased armament, but only three or four were completed. The final version, Ju 290A-9, had reduced armament but more fuel, so that range could be increased to 8300km. The production programme was hit when the Red Army occupied the factories near Prague, but in October 1944 the programme was completely terminated: Germany could no longer afford to build the Ju 290. It needed to concentrate all resources on just a few types.
The Ju 290B, C, D and E models never left the drawing board. "
http://uboat.net/technical/ju290.htm
JU-290
Type: Long Range Transport and Reconnaissance Bomber
Origin: Junkers Flugzeug und Motorenwerke (See comments)
Models: Ju 290A-1 to A-8 and B-1, B-2 and C
First Flight (rebuilt Ju90V5): Early 1939
First Flight (production Ju 290A-0): October 1942
Service Delivery: N/A
Final Delivery: October 1944
Engine:
Ju 290A
Model: BMW 801D
Type: 14-Cylinder Radial
Number: Four
Horsepower: 1,700hp
Ju 290B
Model: BMW 801E
Type: 14-Cylinder Radial
Number: Four
Horsepower: 1,970hp
Fuel:
Capacity: N/A
Type: N/A
Dimensions:
Wing span: 42.00m (137 ft. 9½ in.)
Length: 92 ft 1 in. to 97 ft 9 in.
Length (Ju 290A-5): 28.64m (93 ft. 11½ in.)
Height: 6.83m (22 ft. 4¾ in.)
Wing Surface Area: 203.60m² (2,191.60 sq. ft.)
Weights:
Empty: N/A
Maximum (Ju 290A-5): 44,970kg (99,141 lbs.)
Maximum (Ju 290A-7): 45,400kg (101,413 lbs.)
Maximum (Ju 290B-2): 50,500kg (111,332 lbs.)
Performance:
Maximum Speed: 440km/h (273 mph)
Initial climb: N/A
Service Ceiling: N/A
Range: 3,700 Miles (5950 km)
Range (Ju 290B-2): 4,970 Miles (8000 km)
Armament:
Ju 290A-2:
Five 20mm MG 151
Six 13mm MG 131
Ju 290A-8:
Ten 20mm MG 151
One (or Three) 13mm MG 131
Bomb/Missile Load:
N/A
http://www.warbirdsresourcegroup.org/LRG/ju290.html