Original 427 FE engines were mated to a ZF and destroyed them with their massive torque. The originals had to have a custom transaxle, the T44, made to handle it. You will have the same problem unless you treat the transaxle with respect.
The engine is bigger making adding AC a bit more challenging. Cooling the engine shouldn't be too hard. The only difficult time would be slow speed driving.
The engine is indeed heavier, but if you go with an aluminum block and heads, you shouldn't have a problem