correct dual quad & intake - 66 riviera gs

[66rivgsnewbie]

hello all,

 

i just purchased my first riviera.  it's a 66 gs with dual quads.  i've read a lot of discussions and understand the very rare factory-installed dual quads have the  "mz" code.  i have the "mw" code and have read that some of these had the dual quad kit sent for dealer installation.  i've researched what the correct intake and carbs were sent in the kit, but wasn't able to find any information.  my gs has the offy intake and quadrajet carbs.  does anyone know which intake and carbs came in the kit?

 

thanks,

jeff

Edited February 16, 2020 by 66rivgsnewbie (see edit history)

[8E45E]

Here is a '65:

 

[Ozstatman]

On 2/16/2020 at 3:17 PM, 66rivgsnewbie said:

 i've researched what the correct intake and carbs were sent in the kit, but wasn't able to find any information.  my gs has the offy intake and quadrajet carbs.  does anyone know which intake and carbs came in the kit?

I suspect an OEM intake manifold wouldn't be an Offenhauser.

Edited February 18, 2020 by Ozstatman (see edit history)

[joe_padavano]

5 hours ago, Ozstatman said:

I would suspect the an OEM intake manifold wouldn't be an Offenhauser.

 

Nor did it use spreadbore Qjet carbs. The factory dual quad setup was an iron intake with square bore Carter AFB carbs. The OP's aluminum Offy setup is aftermarket. This is what the factory setup looked like.

 

 

 

 

 

This would be the correct intake and casting number for the 1965-66 cars.

 

Edited February 16, 2020 by joe_padavano (see edit history)

[padgett]

And I need to do a dig to find my Carter book, suspect Jon knows exactly which, and AFAIR only the rear had a choke. think it was 4xxxS. carbs also have date codes. This is what I meant about do you really want judging that strict ? Nearly every component of a '60s GM car has a date code.just like there are ways to tell a '64 GTO from a clone (some require disassembly...)

[joe_padavano]

1 hour ago, padgett said:

 and AFAIR only the rear had a choke.

 

You can see that in the photos I posted.

[padgett]

and just found a Carter book but is only 1921 to 1947, AFBs must be here... somewhere...

 

Have always liked dual quads, had some on my Sunbird, just not 4GCs. Rear primaries are closest to the center of the engine, could cruise at 23 mpg and that was in the last century. (Did 25 with a Rochester large plenium FI on a 327 and met 75 emissions. Firebird club did not like that.

[66rivgsnewbie]

thank you everyone for your comments and expertise.

[zepher]

14 hours ago, 66rivgsnewbie said:

thank you everyone for your comments and expertise.

 

Now we just need to see some pics of your Riviera.  🙂

[66rivgsnewbie]

here you go...

[66rivgsnewbie]

here you go...

[zepher]

Love those hide away lights.

[Pfeil]

On 2/16/2020 at 1:26 PM, padgett said:

 

 

. (Did 25 with a Rochester large plenium FI on a 327 and met 75 emissions. Firebird club did not like that.

 

 That I would love to see. Do you really think you could pass a 1975 EPA certification emission test? A seven bag test from the sub zero cold room to the dyno room and start up and complete driving cycle? Even the state emission test would be hard without a Cat and a air pump. But of course on a state emission test you wouldn't even get to the test because you wouldn't be able to pass a 1975 visual inspection.

Edited February 21, 2020 by Pfeil (see edit history)

[joe_padavano]

2 hours ago, Pfeil said:

 

 That I would love to see. Do you really think you could pass a 1975 EPA certification emission test? A seven bag test from the sub zero cold room to the dyno room and start up and complete driving cycle? Even the state emission test would be hard without a Cat and a air pump. But of course on a state emission test you wouldn't even get to the test because you wouldn't be able to pass a 1975 visual inspection.

 

This is exactly the problem. People don't understand that state-run emissions tests are just spot checks and are nowhere near as rigorous as the EPA tests that manufacturers must perform. A real emissions test takes weeks and costs tens of thousands of dollars to perform. Obviously that isn't practical at the state level every two years. These state tests are simply a spot check at idle and low RPM. If the vehicle passes at those two points, AND all the factory equipment is in place and appears to be functioning, it is ASSUMED that the car is compliant. This is a compromise of practicality vs. accuracy. The reality is that a car modified as stated will NEVER pass the real EPA emissions test for that year.

[padgett]

" Do you really think you could pass a 1975 EPA" Was in 1972.  I was a student at the General Motors Institute (now Kettering) in Flint Michigan at the time. We had SOA test equipment.

[Pfeil]

2 hours ago, padgett said:

" Do you really think you could pass a 1975 EPA" Was in 1972.  I was a student at the General Motors Institute (now Kettering) in Flint Michigan at the time. We had SOA test equipment.

What exactly are you trying to say? You were a student? Have you ever done EPA certification testing?