Aftermarket Holleys all mount the same regardless of what vehicle they are on. The 390 you have would be a Holley square bore. Summit has an adapter plate part# SUM-G1406 for $52.00 and Jegs has a Moroso brand part#710-64966 for $55.99. Keep in mind that these are for adapting the Holley 2 Barrel 2300 series carbs. The stock Motorcraft 2 barrel used on AMC V8's will also fit these adapters.
Jeep #1 = 76 CJ5, 304, T18, Twinstick Dana 20, Lock-Right in front, Yukon HD front axles, One piece axles - Detroit Locker in rear, 2.5" Rancho Springs, 1" lift shackles, 32x11.5 Super Swamper TSL/SX, Warn XD9000i, York OBA.
Jeep #2 = 80 CJ7, 401, T18, D300, 3" Black Diamond Lift, TrXus M/T 33x12.5, Yukon 1 piece axles, Auburn posi in rear, Detroit TrueTrac in front, Ramsey 8000.