RESTAURANT REVIEW SAL’S MEXICAN INN : Say Cheese : This Oxnard institution is a return to the Mexican food of yore--complete with melting <i> queso</i> and un-trendy crisp tacos.

When Sal and Mary Lopez opened their place on Oxnard Boulevard 40 years ago, neither the Latinos nor the Anglos who frequented the restaurant thought much about what was on the menu.

They expected to see exactly what was there: tacos (the hard, or dorado kind), enchiladas, tamales, chile rellenos , tostadas and a few related dishes. Maybe some chile colorado (red) and chile verde (green). Beans and rice, of course.

This was long before California began importing more stylish varieties of Mexican cuisine--or even inventing its own.

There were no gourmet taquerias around, serving “nouvelle” dishes. Most tacos were of the “shell” variety, not soft and yielding. Yet to come were the influences from New Mexico, such as quesadillas with olive paste or tostadas laced with sun-dried tomatoes.

None of that concerned Sal and Mary Lopez then--and it doesn’t concern them now. The menu at Sal’s Mexican Inn is still what a taco-loving, longtime Mexican food aficionado friend of mine calls “uncompromising.”

Except for the prices, Sal and Mary’s place has changed very little. It’s one of the most popular Mexican restaurants in the county. Its 200 seats are usually packed at lunch, and very frequently for dinner. This is a high-volume operation, with fast service and “very hot” plates.

Sal’s is a place where, if you’re ordering something like a combination plate, or a taco and an enchilada, or a tamale, they’re all covered with that layer of cheese. Under the cheese, the going gets good.

But first, you’ve got to wait a bit for the whole thing to cool. I was greedy one day and reached for the plate too soon, burning my hand. A very frustrating experience.

Under the cheese, the meat in the beef taco is, as it should be, shredded, rather than ground or in chunks. The taco shell can be a little chewy, instead of crisp (we’re looking at a commercial tortilla here, none of the handmade models you find at the nouvelle taquerias ). The chicken in the enchiladas is also shredded. Everything that comes with meat has lots of meat. The cornmeal here is not trying to make up the bulk.

The chile relleno isn’t as spicy as it might be--maybe they’ve culled out the peppers trying to pacify the Anglo taste. Tamales are served in a sauce of a spiced, ground beef, although the beef inside is the properly shredded sort. The biggest sellers, says Sal, are the taco and the relleno dinner plates, with the perennial rice and beans, plus a helping of salad. By the time the dish has been piled with the cheesy hot dishes, and rice and beans, the lettuce and bits of tomato resemble a very sad version of salad.

But nobody comes here for a salad.

Aside from the tortilla dishes, but still in the traditional cuisine area, there is a tasty albondigas (meatball) soup and a machaca (shredded beef and scrambled eggs) that comes with red and green peppers and onions mixed in.

Over on the other side of the menu are sandwiches, which seem almost superfluous here.

But there are also gorditas , a sort of Mexican sandwich, in this case made of cornmeal that can get very, shall we say, firm. But the juice of the meats--prepared a sada, adobado, barbacoa or as carnitas --gives a hearty, meaty and intensely satisfying flavor.

The chile colorado dish, and the chile verde dish are big sellers but again, they go too easy on the spices.

Sal’s also boasts a full bar but, unless you’re into tequila, beer has got to be the accompaniment for this food. Unless you prefer the horchata , that popular Mexican rice-water drink.

This is possibly the county’s best example of satisfying, simple Mexican food--the sort many of us Southern Californians grew up with. The newer, more exotic ventures into the south-of- the-border cuisine may be wonderful, but will they ever be quite as satisfying as the kind of food dished up at Sal’s?

* WHERE AND WHEN

Sal’s Mexican Inn, 1450 S. Oxnard Blvd., Oxnard, 483-9015. Open daily 11 a.m.-11 p.m. Credit cards accepted, reservations accepted. Full bar. Lunch or dinner for two, food only, $9-$12. Recommended dishes: Taco dinner, $3.95, Gordita barbacoa , $2.50.