If I have a long term capital gain of $50,000. from a fixer upper classic car sold in 2017 can all the receipts collected thru the past years be claimed on my 2018 taxes

[MichaelL1]

I think you are asking about computing the gain on the sale.

The cost of the classic car sold is what you paid for it, plus the costs of restoration to get it ready to sell.  Your labor does not count but everything you spent to get it restored to be able to sell it would count.

So yes, total all receipts over the years and add those to the purchase price of the car to compute your gain or loss on the sale.  They are not claimed on the 2018 taxes but taken into account when the sale took place, which is 2017, per the question. 

The sale is reported as follows:

To enter your Investments sold

Click on Federal Taxes

Click on Wages and Income

Click on I'll choose what I work on

Scroll down to Investments

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