Thanks to everyone who's pitched in on this one.. But, still struggling...

• Original problem of lean tip was no transfer slots in primary due to too much secondary idle adjustment. Idle speed was too high, which required turning down the primaries to adjust idle speed and then no slots.
• Reduced secondaries idle screw, allowing me to expose the slots correctly in primary. Lean tip in and stumble gone. But there is no way I can get the slots to show in secondaries as well, as idle would be way too high.
• With this solved, problem reversed itself. Ended up too rich (11.5 down to 10.5 AFR) on tip in.
• Opened up the idle air bleeds to 75 (from 71) and put the staple wire in the IFR slots on both metering blocks. Both trying to lean up idle circuit. Mixture screws are at about 1 turn with a standing idle AFR of 12.5 to 13.5
• Also, bumped up the PV from 6.5 to 7.5 (had it handy) to better match my 16-18" vacuum in "D".

Just tested all of this. Still too rich at tip in and very light throttle at 10.5 to 11.5ish, but then AFR gets up to mid 12s to mid 13s with a bit more throttle. Not sure what else to try to lean out the tip in.

Thanks,
Brian

 

Not sure if this gives you any insight but sounds like your carb is similiar to my QF hr680vs I also a 69 main and 74 secondary .. everything on mine but the main jets are stock. Out of the blue I started getting a lean stumble while I was playing with my distributor weights and vac advance can.. I had read if the engine actually stumbles due to timing or something else which causes combustion to not be complete the afr shows a lean condition as well. Oddly I can make my lean stumble go away by advancing the timing but at that point its too far advanced to actually run it that way.
So im struggling to wrap my head around my issue as well. Anyway my mild 355 ran great with the stock 70/74 jetting and air bleeds but it was slightly rich at 2000+ rpm (which I believe is the main circuit) so I went down to a 68 and then back up to a 69.. I do have a larger cam it seems than you since I only have like 13-15" of vacuum in drive depending on timing setting. (when set up correctly at 18 mechanical to get 35 total mech I have 13" which seems low to me) I had different weights before which allowed 12 degrees at idle with 36 max but the car would stall going from park to drive unless I had it at almost 1200rpms in park.

 

Thanks Augie.

Interesting thing about vacuum.. I was at 12-14" when the transfer slots were messed up. When that was fixed, my vacuum jumped to 18-19". Surprising. Seems vacuum can tell you the overall health of the motor, but not if it is carb adjustment or configuration, or timing. That part you gotta find on your own..

 

Looks like im pulling my carb to have a look today, thanks.

 

so I installed a #35 squirter today which took care of my stumble (finally) I still had a stumble even with the transfer slots barely showing but adjusting the rear to be open a bit more and closing the primary blades just a touch while richening the idle screws helped and allowed me to determine I needed more fuel from the squirter. I have a black cam on the way too but I dont think ill need it. do think at this point I need to close the secondary blades back up a bita bit to allow me to adjust the primary so I have just a touch more transfer slot on light cruise.

 

Glad to hear the squirter helped your stumble.

Still struggling over here. Have tried a number of suggested ideas, both here and on a thread at Speed-Talk.com. https://www.speed-talk.com/forum/vie...hp?f=1&t=65048

Not comfortable drilling IFRs, PV channel restrictors, or T-slot restrictors as they are not adjustable on this carb, and can see risk of permanent damage if drills wander, etc. BTW.. Also, rebuilt a 700 CFM Holley DP and tried it with the same results. Too rich at cruise, and too lean at WOT.

Going to take the 650 Brawler back to stock config and start again this weekend. Head is starting to hurt, and nervous about WOT testing at 15-16+ AFR, even with 81 jets in secondaries. Afraid of hurting the motor or myself. No country roads where I am.

Think just missing something more simple, and can't find it.

 

probably addrssed and I missed it but are you able to verify the secondaries are fully opening?