Boeing revealed on Wednesday the imminent release of the final engineering blueprint for its highly-touted 737 MAX, an upgrade of the plane manufacturer's bestselling 737 commercial aircraft.

A final design, Boeing said, should be out by next year, which experts said should consist of bigger but lighter engines plus considerable tweaks on the plane's body in order to accommodate the new power station.

The new engines, Reuters said, will be supplied by the General Electric and Safran joint venture called CFM International.

First introduced four decades ago, Boeing unveiled last year its redesign plans for the mid-sized 737 by specifically replacing its engine with new ones that the company claimed would save fuel by up to 12 percent.

The 737 MAX, according to Reuters, was Boeing's answer to the Airbus A320Neo, also set to be installed with fuel-saving engines that the European plane maker said will deliver fuel efficiency of up to 15 percent to airline customers.

Reducing fuel consumption has become the benchmark of the competition between Airbus and Boeing following the spiralling costs of oil since last year.

Luring airline companies with promises of less energy expenses and subsequent higher profit margins has marked the aviation rivalry of the two giant manufacturers, apart from their trade disputes that presently were being resolved before the World Trade Organisation (WTO).

In a statement, Boeing chief project engineer Michael Teal said that the company's progress so far in realising the advertised features of the 737 MAX has been encouraging at most.

"Based on design work and preliminary testing results, we have even more confidence in our ability to give our customers the fuel savings they need while minimizing the development risk on this program," Reuters reported Teal as saying in Boeing's official news release.

Slight delay, experts said, had attended the finalisation of new 737 engine design as Boeing grappled on fitting the new power source, which reportedly will come with larger engine fans, without much room to operate.

One of the major compromises it agreed to, Boeing said, was the extension of the 737's nose gear, this time stretching to eight inches in the final MAX design, purportedly to provide for sufficient ground clearance without damaging the shell that houses the wider-spanned engine fans.

The adjustments, Boeing assured, will not impact on the reliability that the 737 has been known for, with the company insisting that the plane's dependability-factor "has always been higher than the competitor."

Experts welcomed the development and appeared convinced that Boeing engineers were going to the right direction.

"My feeling about it is what they're saying is plausible. And I'll just wait until we see the results," Hans Weber of Tecop International told Reuters.

To date, the 737 MAX has attracted a total of 737 orders from 15 airlines around the world though Boeing has admitted that only 451 units were considered as sure buys.

Airbus, on the other hand, has announced 1289 confirmed orders for the A320Neo, prompting the company to play up on the edge by marketing the new plane as one of the hottest-selling new passenger plane in history.