capital gain

As per section 2 (47)

transfer includes the conversion of capital asset into stock in tradeof the business carried on by the assessee.

section 45(2)-Notwithstanding anything contained in sub-section (1), the profits or gains arising from the transfer by way of conversion by the owner of a capital asset into, or its treatment by him as, stock-in-trade of a business carried on by him shall be chargeable to income-tax as his income of the previous year in which such stock-in-trade is sold or otherwise transferred by him and, for the purposes of section 48, the fair market value of the asset on the date of such conversion or treatment shall be deemed to be the full value of the consideration received or accruing as a result of the transfer of the capital asset.

Capital gains shall be computed as per the provisions of law applicable in the previous yearin which stock in trade is sold

he can take FMV ason 1-4-1981 as his acquistion cost for computation of capital gains.