Now the in the new generation airliners, specially Boeing use a lot the concept of Combi, KLM was one of the most popular to use that in some of their 747's. I don't know about other airlines but TAP during some time had 3 of their airplanes converted. TAP ordered in early 60's the 707 for their long-haul flights, firstly Africa, and then also to Brazil and USA. 7 707-382B's where used at that time ( CS-TBA until TBG ), latter and because more and more cargo was beeing carried TAP had to look to 707 with cargo door to use in their network too, mainly again to Africa taking in mind that also TAP used their planes to carry cargo for the military forces ( until Portuguese Air Force ordered their 3 707-3F5C's.... but only two were actually delivered, the last one was cancelled! ). So TAP got 3 2nd. hand 707's, 2 ex: Caledonian 707-399C's - CS-TBH and TBI - and one ex: Flying Tigers 707-373C - CS-TBJ.
CS-TBH was always used as combi, normally to Africa but also sometimes to Europe, CS-TBI and CS-TBJ where both used also as combis but also as pure cargo airplanes, flights normally where again to Africa but to LHR too.
After the revolution TAP also received the 2 ex: Portuguese Air Force 707's and again these 2 - CS-TBT and TBU - were pressed to service, CS-TBU actually also flew some all cargo flights too, but soon they found out that this plane was in better condition to fly passengers and combi and CS-TBJ was choosed to be the all cargo 707 until he left TAP in 1987.
TAP also used the 727-100 to make some all cargo flights, normally in Europe but also to Azores, the planes involved where CS-TBO or CS-TBQ, CS-TBO was a QC ( quick-change ) version so it was quite common to see him comming in a cargo flight and in about 2 hours ready to fly a passenger flight or vice-versa!
Here under you'll have a look to photos of the some 707's TAP used as combis and cargo.
Photo © Eduard Marmet
Photo © Urs Ruf - Euro Airport Photography
Photo © Bimbo