Classic/Antique Car Repair: Firing order, spark plug gap, compression stroke

Question
I would like to know the firing order for a 1949 Pontiac flathead straight eight.

Answer
The firing order is 16258374.  If you are asking because the plug wires have gotten mixed up, be sure that you are on the right stroke of the crankshaft by taking out the #1 spark plug and then cranking the engine until you see pressure building in the #1 cylinder (a finger in the hole works just fine!).  Now you know you are on the compression stroke, now is the time to make sure the distributor rotor is pointing at the plug wire socket that goes to #1 cylinder.  If you skip this step, you have a 50-50 chance of getting the wiring 180 degrees out, because the crank goes around twice for each turn of the distributor.

The point gap is 0.016", the spark plug gap is 0.025".

The correct timing is different for early '49s.  Ones with "IGN" marked on the timing indicator are timed to that mark.  Later in 49, they went to a system without that "IGN" mark, in which the correct indicator is the first line of a group of three lines, if you have the standard head.  If you have the high compression head (it will be cast into the top of the head if so, probably the initials "HC"), the correct timing is to the second of the three lines.  The third line is at TDC.

Valve lash is 0.012" hot, for both exhaust and intake valves.

Neat car!  Good luck with it -

Dick