UPDATE 4-Spirit AeroSystems' shares soar on Boeing deal

* Raises 2017 adj. EPS, cash flow forecasts

* Shares hit record high of $72.83

* Q2 profit, revenue beat Street (Adds details; updates shares)

Aug 2 (Reuters) - Spirit AeroSystems Holdings Inc's shares hit a record high after it reached a tentative agreement with Boeing Co on pricing terms related to parts it supplies for aircraft such as the 787 Dreamliner.

The company on Wednesday said it took a $353 million charge, in the second quarter ended June 29, for lowering prices on parts of the 787 aircraft, as part of a long-pending supply deal.

The deal comes a year after Spirit Aero reached a similar agreement with Airbus SE for its A350 XWB aircraft, a competitor to Boeing's Dreamliner.

Boeing, Spirit Aero's biggest customer, and European rival Airbus have been pressing suppliers to cut prices on aircraft parts, as they seek to stay competitive amid burgeoning demand from airlines for more capable planes at lower prices.

"The (deal) removes the major overhang for the stock," Bernstein analyst Douglas Harned said.

Spirit Aero's shares have underperformed the broader Dow Jones U.S. Aerospace index this year, rising just 4.6 percent, compared with a 26.4 percent increase in the index.

The company has been in talks with Boeing related to prices for parts, including fuselage sections, components connecting engines to wings and wing structures for the 787-9 and 787-10 Dreamliners.

Pricing for the initial configuration of Boeing's wide-body 787-8 variant had been established through 2021, however, Spirit Aero and Boeing were yet to determine prices for parts of the 787-9 and 787-10, according to a regulatory filing. (http://bit.ly/2w5SiJS)

Spirit Aero said on Wednesday that the deal was expected to close in the third quarter of 2017, and it would establish prices for the 787 aircraft through 2022.

The agreement will also address "open commercial issues" on a range of Boeing programs, including the single-aisle 737 Max aircraft.

Spirit Aero Chief Executive Tom Gentile said the deal would reduce uncertainty that has long existed with Boeing and preserve the company's ability to meet long-term cash flow goals.

Boeing told Reuters that the deal would provide additional stability to its commercial aircraft unit and reduce business risk.

The world's biggest planemaker also said the agreement would be an important step forward for its "Partnering for Success" program - an initiative it launched in 2012 to reduce costs in collaboration with suppliers.

Spirit Aero raised its full-year adjusted earnings per share forecast to $5.00 to $5.25 from $4.60 to $4.85.

The company also increased its free cash flow forecast for 2017 and 2018. (Reporting by Ankit Ajmera in Bengaluru; Editing by Martina D'Couto)