I am taking apart my fastback and already thinking about some of the things I'll do when I'll put it back together

I currently have headers with a 3" end, and then the exhaust line is reduced down to 2"

Could you please provide pros and cons for the following options:
- Same as current
- 3" at the header and then reduced down to 2.25"
- 3" at the header and then reduced down to 2.5"
- 3" all the way

On the mufflers I was thinking flowmasters 40 - any comments?

Thanks!

 

See if this helps:

 

Great! Thanks James!

 

on my 73 302... when i got it there was deffinatly newer exaust pipesput in (stock headers). my question is kinda two parts...any one know the stock diameter of this engine? i was thinking of just measureing it with a tape or somthing...is there a better way while its still on the car?