If you are talking 401 or 455 and the 800 cfm carb, the only real way to get what you want is to take the rods out of another Buick carbs. The reason is that the torquey motors have a different profile on the metering rods than does a RPM motor. You will notice that the steps are much smaller on the Buick or torque motor. Ex. .062 and .068 whereas a RPM motor will have bigger steps, ie .010 plus changes. Info supplied by Jon at the Carb Shop. So what is the problem using chevy (most common rod) in a Buick? You are never on the money...........alway too fat or too lean. THis can be fixed with an accomaning jet change but you better be good with area equations or have a chassis dyno handy. Bottom line...........stick with the Buick rods or have custom rods made once you know what you need.
You should be able to get jets and metering rods at GM. Q-jets with carb #'s starting with 170 use metering rods with a different taper and are .080" shorter than earlier rods(carb# 70---). 170 carbs started in 1975, and continue to the present. The pre 75 metering rods came with single and double tapers. The rods stamped with 2 digits are single taper, the ones stamped with 2 digits and a "B" are double taper. The GM part # for jets(Q-jet) is 70319-- with the jet size, ex: a 76 jet would be 7031976. Single taper primary metering rods have the prefix 70318--. Double taper rods have the prefix 70348--. A 46B rod would be 7034846. The Buicks used the double taper rods in most cases. I don't believe there were Buick specific rods. If you want to tune Q-jets you need to get the book Rochester carburetors, by Doug Roe. It will tell you everything you need to know about these carbs. The above information came right from it's pages.
www.carbsunlimited.com , i havent ordered from them yet, but am going to in the next few days. be sure to get some airhorn gaskets as well if your going to be taking off the airhorn frequently to make rod and jet changes.
summit carries edelbrock rods and jets. they work in stock rochesters as well as edelbrock performers. when i last bought that stuff, summit was cheaper than any carb shop. jets- http://store.summitracing.com/product.asp?p=519&searchtype=ecat primary rods- http://store.summitracing.com/product.asp?p=2472&searchtype=ecat secondary rods- http://store.summitracing.com/product.asp?p=525&searchtype=ecat hangers- http://store.summitracing.com/product.asp?p=2473&searchtype=ecat
