I know nothing about Speed Demons but on big Holley’s the fuel level should be at the very  bottom of the sight glass.
Fuel should not leak out when the site glass is removed.

You might try upping the idle just to see if a little extra throttle plate opening keeps it from stalling. How tight is your return spring?

Vacuum advance is a loooong time in the past for my old hot rod.
I want my total advance to be @ 36+ or- a dab.....butt stable.
Vac advance (I know the reasoning behind vac. adv.!) is just one more thang to try and keep up with for a very small gain  IMHO.
With a 378 cu. in. Cleveland.....snotty cam....trick heads and....trick carb is a couple more mile per gallon really a concern with  400+ HP in the mix??!
"Com-'on man!"
I'd play with the float level....bump the idle a dab....plug the Vac/adv. and.... see what she does
6s6

Bentworker wrote:

Yesterday I took it out for a 35 mile trip with the float levels lowered and it would still do the stall / idle bounce when returning to idle post burnout.

I took apart the MSD distributor today and was able to swap out the vacuum canister for the delete kit.  Wasn't too bad.  Played around with initial timing.  Seemed like hot starts had the potential to make some racket when I went at or above 16 degrees BTDC initial.  Settled in on just less than 14 degrees initial, about 34 total.  Ran it around on about 2/3rds 91 pump gas and 1/3rd 93 ethanol free.  The car had excellent manners.  I think I may be leaving a little horsepower on the table so I will try a different mechanical advance stop in the distributor to get me up to 36 degrees total.  Making big steps towards this thing having street manners and tire disposal capabilities.  Really happy with how it ran.


My guess is that before I had my initial about 10 degrees, and the vacuum advance would toss another 15 degrees or so on top of that when the throttle snapped shut and the vacuum peaked.  That took the idle timing into the no-go zone and calamity ensued as the engine flat out stall or have this wicked idle bounce as it was chasing its tail timing wise.  This is probably why every single MSD paper I could find said to used the ported vacuum for the advance- and I was using the straight vac port...

Also found this cool white paper of sorts on timing.
http://www.firstfives.org/faq/timing/timing_for_modified_engines.PDF

Sounds like you are "zeroing-in-on-it!!!!"
Play with lighter springs to bring in total advance quicker!
Sounds like the MSD has a BUNCH of adjustments for all different sorts of advance curve.
Like the "white paper" sez....be aware of too much advance!
The Clevland  heads are pretty efficient so 36* may be too much total.
Try bringing it in quicker and limit it to 34-36degrees.
'Some" set ups have the weights wired open so there is NO advance at all!
Good starter and strong battery will crank it  locked out at 36!!
Prolly a racing fuel... drag race piece situation.(good illustration of how all sorts of curves are possible!)
6sally6

 

Is that a Wagner PCV valve you're running?

Bentworker wrote:

Yep- so far so good with the Wagner PCV.

Thanks. I'm about to order one...