Carb Selection for a Mild 400

[73se400]

Currently looking for a suitable carburetor for a street/mild 1973 400 build. Original heads, stock comp ratio, Cl-21-674 284/.484 108 cam (+19 degrees), Performer RPM intake, MSD ignition, and longtubes. 2800 stall. Stock 8 1/4 gears.
Should I go with a 650 Holley or 750 xxx? Currently have a 650 Edelbrock AVS2 that's running way too rich regardless of tune. Car runs great until I try to get it to idle in gear for more than 30 seconds. Planning on drilling holes in the primary throttle plates to help with the idle. Any advice helps.

-EAS

[Nacho-RT74]

stock pistons? too much camshaft for it

I'm a big fan of Thermoquad, but...

[DynoDave]

I can't find a CL21 674 in the current Comp catalog. I did find a CL21 672...the grind seem to get more aggressive the higher the "number" (674 Vs 672), so I have to guess your cam is a little more aggressive than this one.

www.compcams.com/nostalgia-plus-247-254-hydraulic-flat-cam-and-lifter-kit-for-chrysler-383-440.html

But even this one calls for a 3500 stall converter, and 10:1 compression ratio. Your stock engine probably has an advertised compression ratio in the 8 or 8.5:1 range, which when actually measured is probably somewhere in the 7.8:1 - 8.2:1 neighborhood. You're also going to want a pretty healthy gear ratio, like a 3.55 or better I would guess (Comp does not specify one). The power band for this 672 cam is 3000 - 6500 rpm, which I'm going to say is really pushing it for stock heads.

So based on the details I have, I'm inclined to agree with Nacho. You have some mis-matched components there.

Back to your original question, I once again would agree with Nacho on liking the factory TQ, but they are a challenge to tune in that parts are not nearly as available as they are for Holley carbs. The Holley is probably more broadly understood if you need tuning help. That said, if the drivability issues you are looking to cure are caused by mismatched components in the engine, you may not find a carb that will cure those issues.