inline 6 vs. 283

[pimpston65]

so after decoding my new 66 suburban 4x4 (6K1406626910A)i find it came with an inline 6. how would i find which 6 it would have come with? it has a 283ci in it now , but seller says its from a pontiac. i also was reading that a 283 could have been an upgrade. my question. since the numbers for torque and hp are really close would i have a more powerful engine with the 6 in weight savings? does it weight less? and what about fuel savings? i also wanna run ac and stock radio and use the cig outlet for a converter to run a ipod or small bose system on our road trips. if i get the 6 should i just upgrade the charging system? i need help, but on the carryall for now!!!