Totally different...
The SBA 8(a) Business Plan is almost totally different than a standard business plan.  Although you may already have a business plan - even a business plan you used to obtain SBA loans - it will probably be of little use to you in preparing the SBA 8(a) Business Plan.

Establishing 8(a) business development objectives:

Most business plans are for strategic planning, or obtaining financing. By contrast, the SBA 8(a) Business Plan is for the specific purpose of establishing 8(a) business development objectives.

SBA Form 1010C:

Your 8(a) Business Plan will be submitted on SBA Form 1010C. The form asks 52 detailed questions that are specific to the 8(a) program. The questions require comprehensive and detailed answers in written narrative form that address your plan for developing your company through the 8(a) program. Otherwise, SBA will not accept the plan.