Why FTSE 100 dynamos AstraZeneca plc, GKN plc and Diageo plc should deliver stunning long-term growth!

Today I'm looking at three FTSE 100 (INDEXFTSE: UKX) stocks poised to deliver pukka returns.

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Expect healthy returns

Despite the ongoing problem of patent expirations on key labels, I believe AstraZeneca's (LSE: AZN) steadily-improving product pipeline should deliver sterling returns in the years ahead.

The pharma giant has announced a string of regulatory successes in recent weeks, including sign-offs for its BevespiAerosphere COPD product in the US and Tagrisso lung cancer battler in Japan.

And AstraZeneca has late-stage testing data, as well as further regulatory submissions and decisions, expected on more than a dozen more potential earnings drivers during the second half of 2016 alone.

Enduring exclusivity losses are expected to keep the bottom line under the cosh for some time yet, however, and the City expects AstraZeneca to swallow earnings dips of 7% and 2% in 2016 and 2017, respectively.

Still, I reckon AstraZeneca's transformed production pipeline -- helped by a raft of shrewd acquisitions and industry collaborations -- should deliver the goods further out, and fully expect sales to explode as global healthcare demand rises.

Car star

Like AstraZeneca, engineering play GKN (LSE: GKN) has also endured its fair share of revenues woes of late.

Difficulties in the agricultural sector have led to severe sales problems at the firm's Land Systems division, and organic sales here dipped 6% during January-March.

On top of this, slowing demand for civil aeroplanes is denting growth at GKN Aerospace, with the business seeing organic sales flatline during the first quarter.

However, investors should be encouraged by the ongoing progress of GKN Automotive. Organic sales here rose 4% between January and March, prompting GKN to comment that "strong organic growth above the market was achieved in Europe due to new programme launches and the continued strength of premium vehicles."

And I believe surging global car demand across should keep orders of GKN's car parts moving steadily higher. Furthermore, shrewd acquisitions like that of Fokker last year should help the engineer recover from current softness in the aerospace market.

This view is shared by the City, and GKN is anticipated to bounce from a 2% earnings dip in 2016 with an 8% rise next year. I reckon subsequent P/E ratings of 9.7 times and 9.1 times make the Redditch firm a bargain given its hot growth prospects.

Drinks darling

I also believe Diageo(LSE: DGE) remains a top buy for investors seeking stunning long-term returns.

Diageo remains committed to its pan-global acquisition programme, a shrewd strategy as rising personal income levels in developing regions look set to drive drinks demand.

Diageo has steadily built its stake in India's United Spirits and South Africa's United National Breweries in recent years, for example, and made a major statement in 2013 by purchasing Chinese baijiu producer ShuiJingFang in 2013.

And the business can rely on its portfolio of industry-leading labels featuring the likes of Johnnie Walker whisky and Captain Morgan rum to keep driving the top line higher too. These labels command terrific customer loyalty that enable Diageo to hike prices regardless of broader economic pressures.

Consequently the City expects Diageo to rebound from a 1% earnings decline in the year to June 2016 with a 9% advance next year. While subsequent P/E ratings of 21.2 times and 19.5 times may appear conventionally heady, I reckon the drinks darling's terrific brand stable and wide geographical presence fully merit such a premium.

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Royston Wild has no position in any shares mentioned. The Motley Fool UK owns shares of GKN. The Motley Fool UK has recommended AstraZeneca and Diageo. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.