The Firing Order is actually 18436572.
The Date Code will have what looks like a Slotted Screw Head, then a letter, then some numbers, then another Slotted Screw Head.
As mentioned, the ones on the Heads will be under the Valve Cover. The one on the back of the Block will be above the Bell Housing on the Drivers Side, but is really hard to see with the engine in the truck. A sample of your possible Date Code would be: *H44* or *H464* (August 4, 1964) although the Casting Date is usually somewhat before the Engine Date.
The numbers on the Intake (3746826) are the Casting Numbers and look correct for a '61 Chevy truck with a 2-Barrel.
Now that I think of it, the Date Code on the Exhaust is either most likely or always on the back side, where you probably won't be able to see it.
If the Heads are original, they will be your best bet for a Date Code.
Bill
