Tony, number one cylinder is the very first cylinder at the front of the motor. Your timing light has to be hooked up to number one. Your 250 is a later motor from your 62, so you have to go by the specs of that vintage of engine not the vintage of you car. The original six in your car would have been a 194 six originally, unless it was a four cylinder. The 250 is a later version and in my opinion, a far better version of that generation of inline six. There is always a debate as to whether to time an engine with the vacuum advance connected or disconnected. I always followed factory protocol. Good luck. Cheers. George.

There will be a small groove ( nic)on your lower front pulley and should be a small tab on your timming chain cover. Find groove and mark with chalk, I also mark tab at 0 degrees on timming cover. Pic of what should look like.