Republicans plan to release an outline of their tax-reform plan this week, offering some of the first concrete details of a proposal they hope can accelerate American economic growth.

Six top White House officials and lawmakers have led the GOP proposal to overhaul the U.S. tax system. Republicans have set an ambitious goal to pass a bill before the end of the year to broadly chop tax rates and scrap most deductions.

"Republicans are going to announce bold tax reform that grows jobs, grows paychecks and vaults America into the lead," Rep. Kevin Brady, R-Texas, told CNBC on Monday. The chairman of the House Ways and Means Committee noted that the plan will offer specific numbers that include "the lowest rates on business in modern history."

The framework, expected to be released on Wednesday, will likely feature dramatically lower rates for most — if not all — households and businesses, according to several people familiar with the plans. However, as of Sunday night, the so-called Big Six had not yet finalized how much detail to provide on other key elements of tax reform, such as whether to allow full and immediate expensing and perhaps most critically, how to pay for the tax cuts.