Welcome to CHR!

I too love dual quads and while I’ve installed a few have never run them on one of my own – have to put that on my “bucket list” near the ’67 Chevelle! It would appear that you’ve bought these components separately and not as a “kit”? If that’s the case you need to keep a couple things in mind.

Edelbrock has a couple series of 500cfm carburetors – “Thunder” and “Performance".
The Thunder series Edelbrock comes in two versions/series. The 1801(electric choke) and 1802’s (manual choke) are calibrated for single use. They come with the following:
Jets - Primary .86, Secondary .095, Primary Metering Rod .065 x .052, orange spring.

The 1803 and 1804’s are the ones you want for dual quad setup. Ideally, you have one 1803 (electric choke) and one 1804 (manual choke). Difference being:
1803 Jets - Primary .086, Secondary .077; Metering Rods - .065 x .057;
1804 jets - Primary .086, Secondary .077; Metering Rods - .065 x .052; Step-Up Spring - orange (5" Hg).

The Performance Series 500cfm are the 1403 (electric choke) and 1404 (manual choke). Both are factory calibrated with .086 Primary and .095 Secondary jets and .065 x .052 Metering Rods with the orange Step-Up Spring (5" Hg).

All that said – if you don’t have one 1803 and one 1804, you should buy the jets/metering rods to match the above.
.065 x .057 metering rod – part number 1461
.077 secondary jet – part number 1420

I know the differences seem miniscule, but they are important if you want to have success here - idle through WOT.

The manifold you’re using is late model (Vortec heads) typically used where under-hood clearances are an issue. Make sure to mount the 1083 (or the one you modify to meet that spec) to the rear and use Edelbrock progressive linkage (part 7094) or you will be very disappointed.

I'd use Felpro intake manifold gaskets - my personal preference.

Go with 1-1/2 turns on all idle screws to begin and tune accordingly – use a vacuum gauge here

Timing – start with 8 degrees initial and 32-34 degrees total.

Have Fun,
Glenn