: Rochester 4GC carb and Intake manifold

07-12-09, 02:55 PM
Hi guys, I thought I had posted this query yesterday but it weems tht I hadn't, anyway, i have just had the intake manifold on my 1963 series 62 Caddy, with the 390 ci engine rewelded across the centre two ports and have now reassembled this on the car. However it would appear that they have sealed off the small hole that takes a small diameter metal tube from the choke mechanism and connects it to the intake manifold (as i understand to feed heat to the choke bi-metal strip. It would appear that i have now got to remove the intake manifold and have this apperture drilled out again.
Also there is a small metal tube that comes ouot of the base of the carburetor basically in line with the choke mechanism. as i did not take this section apart i am at a loss as to know what connects to this tube. It has been suggested to me that it could be a vacuume feed, but as to where it is fed from i have no idea. so any clues will be most appreciated.
I have photos attached if this helps
Many thanks


07-12-09, 07:40 PM
Here is a link to an ebay auction that has the same carb for sale. Look at the pictures and you can see some sort of connector that is connected to that vaccuum line, a connector that is missing on your carb. also, the tube that has been bent in a downward position to your weld repair, actually should face upward according to these photos. The questionable port is surely a vacuum port. I have an electric choke on my carb, so I cant tell too much about it.

eBay link

http://cgi.ebay.com/ebaymotors/Rochester-4GC-Carburetor-Oldsmobile-400-425_W0QQcmdZViewItemQQ_trkparmsZ65Q3a12Q7c66Q3a2Q7 c39Q3a1Q7c72Q3a1240Q7c293Q3a1Q7c294Q3a50QQ_trksidZ p3286Q2ec0Q2em14QQhashZitem45ebd9c2e2QQitemZ300309 660386QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessor ies

07-12-09, 07:49 PM

I did some more looking, the shaft that your finger is pointing to... is just that.... a shaft, not a port. Look at the ebay listing, there is a linkage that goes to the top of the carb, AS WELL as the bottom, this thing your pointing to also has flats at the tip, where a linkage plate would have fit. I bet if you look into the hole in this thing, it has threads in it for a screw.

07-13-09, 04:56 PM
The choke heat tube should go into a hole in the boss at the end of the exhaust crossover casting - your pipe is pointed straight at the area.

The shaft is the primary butterly shaft, and the choke stepping and pulloff mechanism should be there.

Go to www.jetchip.com and click on the carburetor tab in the lower left of the home page. Have them build you a QJet with electric choke.