what mods can I do and stay smog legal?

[Mr 5 0]

I don't know what the exact CA emission laws are (visit a local MVD office to find out) but I know they're tough and that you have to have all the factory emission equipment in place, so that precludes just tearing it off. Fortunately, most emisssions equipment doesn't have a huge effect on power so that's no big deal.

Whatever you do, be sure your catalytic converters are working properly, as they do the most to reduce emissions. A well-functioning EGR , oxygen sensors (and all the other sensors) need to be in place, too, of course.

You can do cylinder head and intake upgrades as well as add an aftermarket exhaust and underdrive pullies along with the necessary fuel and spark enhancements as long as the fuel mix stays within normal range and the spark is solid. With modern computer-managed engine systems you have a lot of latitude for improving performance on your '88.

FYI: Average MPG should be around 18 on a stock, well-tuned 5.0.