Edelbrock setup for dual quad

Ok, I've got a 1406 on rear and 1405 on front. Backfiring(slight carb fire) thru rear carb. On both carbs I've gone 1 step leaner on both carbs as per Eddy charts. I leaned them down in rods/jets as they are probably "too much" in stock form for the 273. I also turned in idle mixture screws on rear carb. Plugs are fresh last year and I just cleaned them. Advanced timing slightly.
Looking for advice to at least get this to idle.
Suggestions?

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