Had a 177 on an oval port 454 in my first jet. 850 cfm on it. Made 4lbs of boost. It was the way I bought it, it went good. Lotta low end grunt. Boat went mid 70's I guess. But, would definately consider what Liberator is suggesting. I run an 8-71 on my current motor. Love it. If you ever go REAL big inches, you'll already have the blower for it!!