Phenolic Spacer introduced acceleration bog

[Spline64]

Hello,

My carb went out last year so I decided to get a slightly larger carb. I went from an Edlebrock 1406 (600 cfm) on my 454 to an Edlebrock 1806 (650 cfm). Seemed to run fine but didn't really see any performance improvements. After doing the CFM calculation for my motor probably should have stuck with the 1406 but hindsight is 20/20.
My issue is I can't run this carb during summer. It will boil the fuel right out of the bowls if you sit at a stop light long enough, so I figured I'd put on a 1" phenolic spacer (square bore). Well that took care of the boiling over issue but now I have a huge bog when I slam the throttle down for about a second before the engine catches up and takes off.
So I'm wondering have I have accented a "too much carb" issue with the spacer? Would a 1/2 inch spacer give less of a bog? My recent internet research has shown that a big block unless highly modified doesn't need a large CFM due to lower rpm's. I only have a mild cam, Edlebrock street performer intake and headers so not very modified.

Any ideas would be appreciated.

thanks,
Spline64