I have gotten 2 different pairs of vacuum sec Holleys to work on my edelbrock tunnel ram on my 355 sbc. granted it took some work but it was not all that difficult.
A few things i'd like to point out. I picked the edelbrock ram because it has a smaller plenum than many of the others that were available when i originally built the engine in the early 80's. I used lighter than stock secondary springs and i used a vacuum secondary equalizer (a hose than runs from the top of each secondary vacuum housing ---they were sold by Holley - might still be). i also worked on different jets and mettering plates.
I did all this because i intended to drive the car - a lot - on the street. And once done it worked very well , but yeah it was a lot of work. The cam, torque converter and rear gears were all set to work with the engine , worked well from about 2300 up to 6500.
Only real trouble i had was the trans would get a little hot when i cruised at 60 on the interstate because the converter would slip a bit at 2500 rpms or lower..
Anyway the first carbs were 390 cfms they worked great but i later changed them out to 456 cfm ones beacuse the engine seemed to want more fuel on the top end when i ran the car in the 1/4. The car picked up mph when i did that but little to no change in e.t.
With full exhaust and street tires the car run low 12s (best was 12.01) 60 ft time was ridiculous but MPH was around 115 i think i ran 116 or so once . the timeslips are all from the 80's and have since faded so i am only left with my bad memory
I agree for all out power mechanical secondary carbs would work better.