You can do it yourself. There's a book specifically for the Rochester Q-jet I'm reading right now that spells it out in pretty simple terms. It's called "Rochester Carburators, by Doug Row". I only bought it because I thought it would help me to understand my 2G, but it only covers the service and serious tuning of the Q-jet (which I should have guessed before hand!).
You can get it at Amazon.com for pretty cheap.
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'69 3/4 ton C20 2wd w/ 350ci/400THM and a wood bed!
'69 3/4 ton Custom 20 2wd w/ ORIGINAL 350ci/4sp Manual and a wood bed (parts beast).
Seattle, WA.
*See pics of my trucks and project at
www.webshots.com!