Hi everyone. Back again for some advice. Been searching the SBB thread for quite some time. My head is spinning with SCR, DCR, camshafts and just about everything else. Just to refresh everyone, I have a 72 Skylark which I removed the heads to do some cleaning and mods. I thought 72 heads were a strange head since everyone talks about 68-71 heads and I was doomed. Went to my stockpile to find the alternative 71 engine was siezed. OK, took heads off this engine and compared it to the 72 and saw the only visible difference was the AIR holes. (Yes, casting #'s, year on exhaust horn were) Everything else looks the same. I have a few questions some basic some maybe not. First off, most of the links in the sticky or first posts come up as an error, cannot be found. I remember the site was compromised and many posts destroyed. Is this true or am I doing something wrong? Not sure what everyone means by double scallops. It's all 455 posts. No pictures etc. I think it is two coolant passages in the middle of the head. Heads are off and I am going to drop them off at machine shop for cleaning and check for cracks. The heads off the 72 do not have spring dampers on exhaust springs. Has someone been working on these prior? Did 72 have dampers like other years? Looking at possibility about replacing the cam. What kind of SCR will I require for a Crower Level3. Hear lots of good talk about it but don't know if that is a possibility without changing pistons. 91 octane fuel here. Not sure if this can be accomplished with head or block decking. Or, is a Level2 more practical. Have plenty more questions but do not want to go overboard on the first post. Thanks, Chris.