Thanks! nice narrative on heads! I have 4 engines with L98 aluminum heads, on the street, they work great for me! Again, I'm looking for a nice powerplant with strong, reliable street manners, and these fit the bill! 90% of my customers that are not into "potatoe-potatoe" idle manners,loading up, and running on premium fuel, the L98 heads are affordable, allow increased compression on regular fuel, and are cheaply upgraded to LT4 valvetrain over the counter!