ok..I know that the letters in 12a or 13b signify either carb or fuel inj, right? if this is correct which letter corresponds to what? any info on this will be appreciated, thank you

 

The letters actually has nothing to do with carb or EFI at all.

Generally carbed 13B`s and 12A`s are found up to 84, when they started to use EFI on the GLS-SE. (They also discontinued the 12A in 85)
Some of the 12A`s had EFI before 1985 (the 12A turbo) but none where sold in the USA if i remember correctly

The carbed 13B`s where 4 ports and found on RX-5`s, REPU`s and so on.

Hope that clears things up for you!

 

thank you, that did clear some things up