HELP!I bought my '68-400 last fall, it has good power and I was sure it was A-400 but I knew it wasn't the orginal engine (I'am experienced with pontiacs from that era). I've driven aprox. 500 miles in it.trying to tune it up for spring & indentifying exactly what I have I'am confused!!! the engine block has a code of "YH" stamped on it. Where do I fine the head stamped codes? It has a regular distributor and the points&rotor look fine, but the plugs are old & fouled & are motorcraft #ASF52C any sugestions on what plugs to use?
