I have been in the world of aviation for a while, always able to recognize differences between aircraft, but I still have a doubt.
Some planes, in the specific case of Boeing and Airbus, have the series of, lets say 727-200, and it also had 727-100, but when I see some of the pictures here on the gallery, they appear as 727-264, or other number in the series. When I see the pictures the aircraft type appears as 737-4Q8 for example, not as B737-400.
Airbus is also like that, an Airbus 330-300 would appear as A330-323, or something alike.
I wonder how to interpret the number of the series, if those numbers mean minor changes or something like that, if anybody knows what that means, or if anybody knows a link with information on that it would be helpful.
I can tell between a 747-200 and a 747-300, but not between a 747-432 and a 747-474  

thanks
apg

For Boeing it is the customer code that follows. More information here:

http://en.wikipedia.org/wiki/Boeing_customer_code

For Airbus it is based on engine type. Here is a list i put together once:

Model Engine Type
A300B2-1A General Electric CF6-50A
A300B2-1C General Electric CF6-50C
A300B2-203 General Electric CF6-50C2
A300B2K-3C General Electric CF6-50CR
A300B4-103 General Electric CF6-50C2
A300B4-120 Pratt & Whitney JT9D-59A
A300B4-203 General Electric CF6-50C2
A300B4-220 Pratt & Whitney JT9D-59A
A300B4-2C General Electric CF6-50C
A300B4-601 General Electric CF6-80C2A1
A300B4-603 General Electric CF6-80C2A3
A300B4-605R General Electric CF6-80C2A5
A300B4-620 Pratt & Whitney JT9D-7R4H1
A300B4-622 Pratt & Whitney PW4158
A300B4-622R Pratt & Whitney PW4158
A300C4-605R General Electric CF6-80C2A5
A300F4-605R General Electric CF6-80C2A5 or 2A5F
A300F4-622R Pratt & Whitney PW4158
A310-203 General Electric CF6-80A3
A310-203C General Electric CF6-80A3
A310-204 General Electric CF6-80C2A2
A310-221 Pratt & Whitney JT9D-7R4D1
A310-222 Pratt & Whitney JT9D-7R4E1
A310-304 General Electric CF6-80C2A2
A310-308 General Electric CF6-80C2A8 or CF6-80C2A2
A310-322 Pratt & Whitney JT9D-7R4E1
A310-324 Pratt & Whitney PW4152
A310-325 Pratt & Whitney PW4156A
A318-111 CFM56-5B8/P
A318-112 CFM56-5B9/P
A318-121 PW6122A
A318-122 PW6124A
A319-111 CFM56-5B5 or 5B5/P
A319-112 CFM56-5B6 or 5B6/P or 5B6/2P
A319-113 CFM56-5A4 or 5A4/F
A319-114 CFM56-5A5 or 5A5/F
A319-115 CFM56-5B7 or 5B7/P
A319-131 IAE Model V2522-A5
A319-132 IAE Model V2524-A5
A319-133 IAE Model V2527M-A5
A320-111 CFM56-5A1 or 5A1/F
A320-211 CFM56-5A1 or 5A1/F
A320-212 CFM56-5A3
A320-214 CFM56-5B4 or 5B4/P or 5B4/2P
A320-216 CFM56-5B6
A320-231 IAE Model V2500-A1
A320-232 IAE Model V2527-A5
A320-233 IAE Model V2527E-A5
A321-111 CFM56-5B1 or 5B1/P or 5B1/2P
A321-112 CFM56-5B2 or 5B2/P
A321-131 IAE Model V2350-A5
A321-211 CFM56-5B3 or 5B3/P or 5B3/2P
A321-212 CFM56-5B1 or 5B1/P or 5B1/2P
A321-213 CFM56-5B2 or 5B2/P
A321-231 IAE Model V2533-A5
A321-232 IAE Model V2530-A5
A330-201 GE CF6-80E1A2
A330-202 GE CF6-80E1A4 / CF6-80E1A4B
A330-203 GE CF6-80E1A3
A330-221 PW4164
A330-222 PW4168
A330-223 PW4168A / PW4168A-1D / PW4168B / PW4170
A330-223F PW4170
A330-243 RR Trent 772B-60
A330-243F RR Trent 772B-60
A330-244 RR Trent 775-60
A330-301 GE CF6-80E1A2
A330-302 GE CF6-80E1A4 / CF6-80E1A4B
A330-303 GE CF6-80E1A3
A330-321 PW4164
A330-322 PW4168
A330-323 PW4168A / PW4168A-1D / PW4168B / PW4170
A330-341 RR Trent 768-60
A330-342 RR Trent 772-60
A330-343 RR Trent 772B-60
A330-343 RR Trent 772C-60
A340-211 CFM 56-5C2
A340-212 CFM 56-5C3
A340-213 CFM 56-5C4
A340-311 CFM 56-5C2
A340-312 CFM 56-5C3
A340-313 CFM 56-5C4
A340-541 RR Trent 553-61
A340-642 RR Trent 556-61
A380-841 RR Trent 970/B
A380-842 RR Trent 972/B
A380-843F RR Trent 977/B
A380-861 GP 7270
A380-863F GP 7277

The last two digits of the Boeing number identifies the customer.

Quoting tod (Reply 2): The last two digits of the Boeing number identifies the customer.

Do not sound like I am picking nits here but the last 2 digits identifies the original ordering customer.
Many aircraft have lives after the original customer and I believe there were a few that were ordered by one airline and sold to another before paint.

Okie

My incomplete list including Airbus, Boeing customer codes, DC-9, 707, 727, Tristar:

http://www.rosboch.net/aviation.htm#Codes

Quoting okie (Reply 3): Do not sound like I am picking nits here but the last 2 digits identifies the original ordering customer. Many aircraft have lives after the original customer and I believe there were a few that were ordered by one airline and sold to another before paint.

Of course.
Some airline IPC effectivity pages are full of random suffix digits.