Being old I grew up with Cars and Cars Conversions ... it was the only mag that dealt with modified cars at the time. I can remember rushing out to get the latest one that featured the all new KAD 16V head and a few months before that they featured a mini with a alfa twin cam engine and gearbox. The technical section featured loads of questions on minis and on escorts and that was about it.
One of the things you do notice is the quality of the cars is much the same, the main difference now is that a lot of people pay to get the mods done, back in the 70's and 80's you did it yourself or got mates to help out.
The other thing is the quality of the writing - the features were much more professionally written, maybe it was just a style thing but you got more detail and technical info .... CCC used to put the cars on a dyno, so all these mini's with 145BHP 1380's featured today would have been put through their paces, I think it meant people produced less BS regarding what they were actually building.