hey guys my chevelle has a lil carb problem and i want to know what kind i should replace it with? now the engine looks a lil beat up and probally has over 100xxx miles on it,but it runs strong.im not to sure but i think its a rochester at the moment.basiclly when i drive on the road it drives good but once i try to floor it it seems to bog for a second then kicks in.so i dont know what should i do? thanks guys(by the way im a lil tired so forgive me if i dont make sense)

Sounds like a quadrajet 4 barrel the needs a little tweak of the upper secondary air valve.

Those carbs have a nick name (QUADRABOG) just because of just what your describing getteing a bog/loss of power for a few seconds when you nail it then it picks back up and takes off just fine but they are actually a great carb when tuned correctly.

There is a spring that needs to be adj a little tighter so the upper sec airvalve opens a little slower when you floor it which will get rid of the bog.

It's kind of hard to find if you dont know where it is,its under the top/airhorn part of the carb on the back pass side and has an allen head bolt that you loosen then use a screwdriver in upper sec airvalve shaft to tighten the spring a little bit for more tension . Then re-tightem the allen head screw while still holding the spring tension with the screw driver while tightening the allen head screw and thats it. Takes 5 mins to do this once you know where it is and how to do it.

This could also be made worse by a worn out accelorator pump in which that case you should freshen/rbld the carb.

Search quadrajet online and you will find rebuild/perf info on these carbs that will include pics of just where to make that adj.

If it turns out you have a 2 barrel carb your accelorator pump may be shot and carb needs a refresh/rbld.

Scott

wow i realy appreciate that and yes it is a 4 barrel.i am going to try this hopefully it works thanks alot man

There's also the book by Doug Roe specifying Q-jets.