If mechanical, and you are making no more than about 400 hp, a stock type replacement will work. You will need 3/8" fuel line if the power is over 350 hp.
If your engine makes over 400hp, I would recommend this pump:
http://www.robbmcperformance.com/products/fordfe550.html
up to about 550 hp. You will need 1/2" fuel line if the engine produces over about 450hp.
Over 550hp, this is the only mechanical pump:
http://www.robbmcperformance.com/products/fordfe1100.html
1/2" line will work up to about 750hp at which point you will need 5/8" line.
