I run my RB slightly rich on the top and slightly lean on the bottom. Runs like a swiss clock!!!! Try a hot plug. Run it around and try to get it up to temp. Lean out the lsn until you get a good snap on the low end. Then lean out your hsn but not a lot!!! Then go back to the lsn and lean or richen it depending on performance. Then lower your idle stop screw to where your engine will purr like a kitten!! Lean out your lsn till it holds a good idle and doesnt load up. Dont worry to much about the top end. Its a S7!!! Your only using top end for about 3 to 5 seconds depending on how big your track is. Concentrate on your lsn. Hope this helps. Keep us informed.