Pulte Home Corp., which has been building houses here since 1964, has split its Maryland-Virginia operations and plans to increase production from last year's 400 units to more than 500 in 1978.

Roy F. Krag, president of the local operation of the Detroit-based, publicly owned firm, said that growth plans prompted a realignment.

Krag heads the new western Maryland division, which covers Pulte residential operations in Montgomery and Frederick counties and Northern Virginia.

L. Raymond Smith, who has been with Pulte for nine years as vice president responsible for land acquisition and development, has been named president of the new eastern Maryland division covering operations in Prince George's Howard, Anne Arundel, Charles and Baltimore counties.

Ray Crace is construction manager and Mark Rubin marketing and sales director in the western division. In eastern Maryland, Kevin Gilligan is construction manager and Roland Grice heads sales and marketing.

A third Pulte division for custom home construction has been organized under Roger Schmidt, who will develop and build hig-priced houses on an individual basis.

Krag, who came here last year to head what was then the Maryland division, said that the new alignment was set up to enable Pulte to expand its residential building and selling operations in this area and "to broaden further the styles, sizes and price ranges of houses to be built here."

In terms of new product offerings this year, Pulte plans to have two-story town houses available this summer in St. Charles for "slightly less than $40,000," Smith said. The western Maryland division has opened a community called Fox Vale Farms in the Great Falls, area, just east of Rte. 7 on Georgetown Pike. Prices there begin in the upper $90,000s.

Krag said Pulte plans to build both traditional and "soft contemporary" single houses, town houses and semi-detached houses in varied price ranges in 20 communities by the end of this year. He said the 1978 sales volume is expected to total $35 million, or $15 million more than the total sales in 1977 in this area.

If the housing market continues strong into 1979, he said the total volume of sales could rise to more than 800 dwellings, for a total volume of nearly $60 million.

"Our operation heree is different from those of other national firms," Krag added, "because we are autonomous from the home office in Detroit and free to develop both houses and communities to meet the changing needs of consumers in this area. Competitive firms of our size tend to build the same houses throughout the country."

Areas in which Pulte houses are scheduled to be introduced later this year include Annapolis, Laurel, Oxon Hill. Potomac-Darnestown and Goshen. The firm will continue to build in St. Charles, Germantown, Frederick, Burke Centre and Baltimore County.

Nationally, the Pulte annual report stated the firm delivered 3,082 single houses last year at an average price of approximately $45,000.