Hello, a friend is putting in his fiesta mk2 a 2.0 complete zetec engine. He will put a pair of 45 Dcoes, but the pair he is mounting is 3 progression hole type.

My question is : Why the zetec need 5 progression hole type? and can I drill the two suplementary holes in the carbs?.

Money is an important question , my friend do not like to buy another pair of Dcoes. With the 3 progression holes the engine will run smooth?

Any help will be appreciated