Edelbrock carb guys

Hello, I talked with the guys at Edelbrock in reguards to weather I could change my 4706 600 carb into a 500 cfm by changing the booster venturies since that is the only difference I could see in the carbs. They said yes, that was all I had to do and the boosters from a carter carb should work too. I picked up a carter 4761 500 carb. I didn't think to ask but do I only need to change the primary venturies? I see the secondary boosters will not interchange or don't look like they will. The edlbrock seconday boosters for the 500 carb are larger than the carters. it looks like they have to be to clear the butterflies. They are near the top on the Edelbrock and at the bottom of the carb on the carter. I hope that makes sence. So do I only need to change the primary boosters?
Thanks again

This is a picture of the edelbrock 500

http://media.photobucket.com/image/e...eg_M/bores.jpg

and this is the carter 500 next to a edelbrock carb

http://cliff.hostkansas.com/pffimage..._venturies.JPG
Author: Furios66