Cliff's Quadrajet Parts and Rebuild Kits

Is there a way to make the bypass air system easily adjustable via some sort of jets or a screw?

It would be cool to not have to move the throttle plates and uncover the transfer slots to adjust idle speed.

Welcome to the Forums!

The throttle blades should be flat.
There is absolutely NO reason for curved or bent blades.

 Back in the early seventies, I picked up a 64 Pontiac Grand Prix. It had a factory 421 4 bbl (real Carter AFB) with a Roto Hydromatic (Slim Jim).
 The Slim Jim transmission had no stator / torque converter. L was a vertiable ratio 3.03:1 range. Then when it shifted into S (1.58 ratio), it would couple hard with allmost zero slippage. D range was 1:1 and also coupled hard with all most zero slippage.
 The transmission worked well when it felt like it, looking back I think it was tempature sensitive. One time I stayed side by side with a brand new Kawasaki Crazy KZ motor cycle. Don't get my wrong, he beat me but he couldn't loose me..
 
 The only car I can remember from the sixties, that used Ported Spark advance, was was Roto Hydramatic (Slim Jim) equiped 61 to 64 B body Pontiacs with the Trophy Series 389 and 421 engines. If you look at the front, bottom, left corner of the Carter AFB equiped Trophy motors, they had a vacuum outlet for the vacuum advance.
I don't remember if the Tri Power versions came with this feature.
I know the 1958 to 64, four speed Super Hydramatic equiped Bonnevilles and Star Chiefs came with regular manifold vacuum advances. Note that the 4 speed Super Hydramatic transmissions were light years stronger and better performers than the Roto Hydramatics...

You may need to run a little more total timing but it's not always best to increase initial timing to get it.  Too much initial often results in difficult hot restarts.  For most well thought out engine builds I like to use around 10-12 initial, 10-11 mechanical (20-22 at the crank), and 10-15 degrees from the VA.  In most cases I use ported vacuum to the advance as my engines are higher compression wider LSA camshafts which promote good cylinder pressure at low RPM's so no need to run a butt-load of initial timing to make the engine happy.

When I custom tune engines brought here I use similar numbers unless they are lower compression with big cams or tight LSA.  I always address idle fuel delivery as well and when I get that up to par it's still rare to need a lot of timing at idle speed for most engines. 

Anyhow, it is best to make very small changes with total timing.  Right now you have 26 degrees total timing at full load.  Most engines I've tuned like closer to 30-34 degrees with some liking a bit more than that.  Some engines like a tad less so be conservative when advancing the timing as detonation may occur and it will destroy the best prepared engine......

I agree, up the timing some. If that's too much @ idle, switch to ported vacuum.
Easy to try.

QJ