What do you think the max hp you could kick out of a 1.5 sohc 16 valve d15b7 del sol engine without a turbo?

The answer depends greatly on the reliability expected. Most people read magazine articles and internet web pages where others are building performance engines and bolting on performance parts and achieving a maximum of 200/hp per Liter. However most of these modifications are not street legal. So the answer all depends on the use of the vehicle which will contain your performance 1.5L engine. In addition to that, once you change the horse power rating of your engine, then everything else relate to that engine must change as well. The transmission and devices providing power to the transmission, the differential, the axels and other parts must be graded as well, in order to handle the extra horsepower and torque coming from the high output engine. So your answer is not one sided its multifaceted and requires some Engineering level mathematics in order to get all the bits correctly sorted out.