1970 7040268 Pontiac QJ numbers?

[thor7726]

This past summer I purchase a 1970 Pontiac 455HO engine.  I spent that last 6 months rebuilding it back to stock except for its bored .030 over and has a ram air IV cam.  Unfortunately the original QJ is long gone and it came with a Holly.  I just purchased the correct QJ on ebay a 7040268.  Its on its way and as soon as I get it I want to check it over to make sure it is all numbers matching as the seller stated.  It has the date code and plant stamp and they look factory from the pictures. Here are some questions:

1.)  What part numbers can I check to make sure it is correct?

2.)  Did the 7040268 come with a hot idle compensator?

3.) What jets, rods, idle tube diameter, etc is this carb supposed to have?

4.) Can I get the jets, idle tube diameter, rods, etc information for the 7040270 carb as well? ( Iwas told with my cam this carb would work better and I might set up the 7040268 to run like the 7040270.)   

5.) What else should I look for???

 Thanks in advance for the help.  I'm new to QJ and dont want to get screwed!  I can send pictures if that would help.

[thor7726]

Looking further into it, what casting number should the air horn be?  It looks like the bowl and base plate is correct I just cannot find any information on the air horn.

Thanks again!

[Ethan1]

This past summer I purchase a 1970 Pontiac 455HO engine.  I spent that last 6 months rebuilding it back to stock except for its bored .030 over and has a ram air IV cam.  Unfortunately the original QJ is long gone and it came with a Holly.  I just purchased the correct QJ on ebay a 7040268.  Its on its way and as soon as I get it I want to check it over to make sure it is all numbers matching as the seller stated.  It has the date code and plant stamp and they look factory from the pictures. Here are some questions:

1.)  What part numbers can I check to make sure it is correct?

2.)  Did the 7040268 come with a hot idle compensator?

3.) What jets, rods, idle tube diameter, etc is this carb supposed to have?

4.) Can I get the jets, idle tube diameter, rods, etc information for the 7040270 carb as well? ( Iwas told with my cam this carb would work better and I might set up the 7040268 to run like the 7040270.)   

5.) What else should I look for???

 Thanks in advance for the help.  I'm new to QJ and dont want to get screwed!  I can send pictures if that would help.

 Welcome to CHP!

 1. Not sure what the correct part number for the air horn should be. I know the manual says the air horn "assembly" part number is 7036886. Sorry I cannot help much on that.

 2. Yes, Qjet 7040268 came with the hot idle compensator. Part number 7032706.

 3. Stock jets and rods were .071" Primary Jets, 42 Primary Metering Rods and CC Secondary Metering Rods. Not sure on idle tube diameter. They did not put those sizes in the manual. Cliff, would be best to answer.

 4. Stock jets and rods for 7040270 were .070" Primary Jets, 39 Primary Rods and CC Secondary Metering Rods.

 5. I think you pretty much asked all the right questions. As of right now, I cannot think of any other things to check for. Just be sure to get a SR kit and accelerator pump from Cliff.

[Cliff Ruggles]

The airhorn used on the 7040268 is a completely different part than used on the 7040270 Ram Air carburetor, so don't compare jets and metering rods used between the two carburetors.  The 7040268 used a primary POE system so it's going to use different jets/metering rods.

The RAIV cam will also require idle system modifications to the 7040268, and different tuning parts.  I can help with those items and put a custom kit together for it with tuning parts, we do this all the time to take the guesswork out  and make for a good end result.....Cliff