Alright guys I am getting ready to rebuild the Quadrajet for the 403 that is going into my Cutlass.
The carb I am using is the stock one that came on the 403, at least for now and I just want to refresh it. Anyone here have experience rebuilding one of these old Rochesters and have any pearls of wisdom that they would like to pass along? Are there any modifications that I should make while I have the thing torn apart?
Anyone have ideas on the best place to get a rebuild kit from? I have heard both good and bad things about Cliff's High Performance both in their service and their kits. I do have Cliff's book on rebuilding the carbs which seems fairly good. I also have found a place called quadrajetparts.com though I have never really heard anything about them.
What year is the carb?
A lot of folks will tell you all about leaking bowl plugs on Q-jets but that was pretty much a non-issue after the mid 1970s.
Is this a computer controlled Q-jet or a normal one?
If you're going for better performance, ditch the inlet-mounted fuel filter and go with a bigger in-line filter after the pump. The float bowl is small so delivery is important.
There is usually a black plastic thing on the passenger's side of the float bowl. This is a blanking plug to fill the space that an aneroid diaphragm fit in on some of the early carbs. I usually leave the plug out to create more room for fuel.
Don't mess with the APT circuit unless you fully understand what it does. The factory setting is generally on the money. If you know the APT hasn't been fooled with, leave it alone. If it has been messed with, the book will give you a base setting to work from (3.5 turns out I think) and tell you how to make it adjustable without having to open the carb up.
Make sure the secondary air doors and secondary trottle plate can open all the way. V6 carbs generally had the air door opening restricted for less flow. 1st gen firebird Q-jets had the secondary throttle plate opening restricted so the GTO would have more hp on the same engine.
Other than that stuff, it's all laid out really well in Cliff's book.
He did the Q-jet on one of my friends cars. A 1965 Catalina 421SD and it does 12's. It's not solely from the carb work but Cliff really set the carb up well.
Shawn
The engine came from a '78 Delta 88 Pace Car and I am sure it is the original '78 non computer carb and basically looks like nothing has ever been done to it.
From what I was able to find out about the car it was owned by an old lady that her and her husband had owned it since new, when she passed her kids did not want the car and to the yard it went.
Sounds like an easy rebuild, are you using Cliffs kit?
I bought a rear choke pull off from quadrajetparts.com this week for a 70 Buick. Quick shipping and packed well. I don't know how their prices compare with Cliffs. By the time Cliff returned my message to say they had the part available but not listed on their site I'd already received the part from Qjet.com. because it was listed on their website so I'd just ordered it.
In reply to Trans_Maro:
Haven't got a kit yet I was wanting to find out where others got theirs first to make sure I didn't get a crappy kit.
I've heard good things about Cliffs kits but haven't used them myself.
Apparently you get new floats and a good, alcohol-resistant accel pump with his kits plus a whole lot more little items you need.
A lot of auto parts store kits are old stock now, that means the accelerator pump rubber may not be compatible with the ethanol in modern fuels. If the rubber is black, there's a good bet it will just turn to goo in the carb.
He also sells a kit to re-bush the throttle shaft holes if they're worn.
The downside is, trying to get in touch with him. He's a very busy guy with a waiting list for carb service.
Shawn
