Top 5 recievers of the 70's and 80's ????

The Concept receivers were very good. 
The Grundig receivers, when match with Grundig speakers are out of this world. 

Fascinating. Had no idea there even were any good receivers.

Sansui 9090db

onkyo tx-890
 Old Yamaha receivers

I enjoyed a Marantz 2275 and later a Tandberg TR2080

Fun topic for sure 👍

I’m more of an Integrated collector but do enjoy a Marantz 2330 (restored by Many Moons Audio) that should qualify. 
Beautiful looking single year (1st gen - 1979) production that, I believe, all featured engraved faceplates. Looks particularly snazzy wearing it’s Pathe Wings walnut WC43 cabinet.

Others to consider would be Sansui G8000, Pioneer SX1250, Concept 16.5 & Kyocera R861. The Pioneer because it’s all discrete and AFAIK the only receiver that doubled down power into a 4 ohm load.

Honorable mentions to TwinPower HK units, Sherwood & Sony