My frame height is about 6 or 7" off the ground and my side pipes lowest point is about the same as yours. My lowest point on my car is my Lakewood bellhousing and it sits only 3 1/2" off the ground, my Canton
oil pan rides approx. 4 1/4" off the ground. I avoid speed bumps but for almost four years I haven't had any problems except ocassionally when I offload my car from my trailer. I have had my bellhousing scrape the hindged portion of my ramp when I am backing the Cobra out. I will be cutting about an inch off the bottom of my bellhousing the next time I change out my clutch.
I have thought about going with longer springs and shocks but I don't know about changing the geometry of my upper and lower A Arms.
Clois