I build both. Dirt motors are 90% of my business. The past few years, I have not been as busy due to the fact lots of guys have sold out or just quit for awhile due to lack of money. Most of the dirt motors are the "small" block Chevys. In the past, I would do 10-15 motors during the winter. The last couple winters, it is down to 3-5. Summer is usually slow, but that's when I race, so I like that!!