My timing is a bit over 16, was 11. 5 stock, should have been 13. 5.
Anyway, it does rattle more when cold, and I suppose if it was real cold, starting may not be as easy. 15. 5 - 16 is the established best for slight mods and all around performance / economy.
If you do not put in the AFC springs with your new plate, you need to back off the star wheel on the AFC all the way and then trim it up to suit. The stock AFC is very tight on smoke and is very slow to chase the boost up with fuel. In all likely hood you are running on your AFC, and the link is not even touching the plate until higher rpm is reached.
Back the star wheel off, and if you do not get any smoke on accelleration, install the AFC spring kit. Once you get fuel in, the boost will come up quick and allow additional fuel until you get up on the plate.
I put the #11 plate, 285hp, 685 torque and the AFC kit in mine at the same time and adjusted per instructions, and it does pull hard in the gears and set you back in the seat some.
If you still think it's the plate and not the AFC, mark the position of the plate and slide it up . 030". That is approximate increase to the next larger plate. The reason to mark it is so you can return to the stock position if needed.
Doug Rees