That would be the later MR3 Phase 3 - Viper turbojets in outboard nacelles. One of those ideas that probably seemed like a good idea at the time!
I've built several Revell AEW and MR3 kits as well as the Airfix MR2 for various customers. The Airfix one is probably an easier build (less flash, better fit) but the Revell kits look more 'rivety'. That last word may well have been made up....
Really nice kits from both manufacturers though - so you can't go too far wrong if you opt for one or the other. A Shack of any flavour looks suitably impressIve when finished.