I replaced my hard brake lines with Dorman stainless preformed kit and removed the abs module, I have the fitting for the rear of the prop valve but two of the fitting on the hard lines are the wrong size. My first thought is to cut off the wrong size fittings and re-flare the tube with the right size fitting, Is there another option ?

 

Cutting and re-flaring is the standard fix. Make sure you use a double flare for safety. The only real alternative is to find a different pre-bent line kit that matches your prop valve fittings, but that's likely more hassle and cost than just fixing the lines you have.

 

Use fitting adapters between your line ends and the prop valve.