Will my gas mileage drop dramatically with 272 cams?

[Onefast99gsx]

Hello.

I'm getting 272 cams in the spring to compliment my PTE 50trim and 780cc injectors. Can someone tell me if my gas mileage is going to suck because of the longer duration of the cams? Regardless of the answer, i'm still gonna get them. I just wanna know what to expect.

Thanks.