Another 340 J & O head thread (what do i have?)

thanks guys, we used grade 8, actually had to run to TSC since i didn't have any long enough on hand. just got nervous and decided not to use the 9 & 3 o'clock ears since they made me nervous.

i also did some more vehicle/engine decoding. if any of you want pics let me know. this is all new to me so it was exciting detective work to me.