most tuners will recommend replacing the fuel pump for an uprated one. i had twin 40's with a facet red top pump, and malpassi fpr. i recommend them as best on market.

are you also getting any head work done? because twin 40's only really benefit from a head with larger ports and a higher profile cam etc. ive seen xr2's etc with only very minimal gains after installing twin carbs because the standard head was restricting the flow.

I also recommend taking them to an expert to get them properly jetted and set up for your engine because that is some fiddly shit.