Thermoquad carb 6455S, 1974, 360 engine HP

Looking for a good core ready for cleaning and rebuilding
1/2 primaries, 800 CFM,
360 HP, l974

Still don't understand the difference between 800 and 850 cfm

I have lots of spare parts,

the main things I Need :

1 No frozen idle mix screws

2 All linkage undamaged and operating freely

3 fuel bowl lid , fuel bowl, and throttle plate to be all good

I have this one to use now, need a duplicate when I get the MOD MAN
Magnum intake with the dual carb option