Not really. In the 70s , cars could do 233mph compared to 187mph in thre 60s, according to Google. How fast nowadays, certainly not faster than 233mph I think.
Ultimate straight line speed isn't everything - unless you're drag racing.
Back in the 1970s, the chassis were made aircraft-style, riveted aluminium. Tended to go into origami mode when crashed. These are nowhere near as stiff as today's carbon tubs, and this makes a massive difference in handling. 70s cars were quite often sideways - when you're doing that, you're scrubbing off speed and losing time. Mechanical grip is so much better these days.
Tyre technology - tyres are grippier and more predictable. It's not my area of ken, so can't comment so much on this.
Aerodynamics are so much better - or rather, the understanding of aerodynamics is so much better. Which means the car is pushed into the track more, so more consistent contact and less sliding around.
You've gone from 4-speed hewland manual gearboxes to 7-speed seamless shifting automatics - shifts are quicker, not much for an individual shift, but multiply that over a whole race distance...
There might be some other things that spring to mind, but that's pretty well much it in a nutshell.