I have the HobbyBoss 1/72 F-84E, the ancient Heller F-84G and the Hasegawa P-47D. The HobbyBoss is a better kit, with more detail and engraved (vs. raised) panel lines. It's also a simpler construction. Both F-84 kits match well in length, down to most panel lines and access hatches. The P-47 wing fits well with either kit, with only minor surgery.
Shortening either F-84 kit by 5.3mm wouldn't be too hard, except for the canopy section. The F-84 canopy is both longer and wider than the P-47 canopy, so considerable plastic surgery would be required around the mid to rear section of the cockpit. Surprisingly, the windscreen section of the P-47 canopy fits the HobbyBoss kit petty well.
There's a conversion of the Heller F-84G to F-84B on
Britmodeller