'71 6500 RPM Tach

[SS454Elky]

I just joined this BB and am amazed at the amount of knowledge here. I was hoping someone could help mw with a question I have about my '71 SS454 ElCamino. I bought this car way back in 1980 and am just now getting around to restoring it. It is a SS454/M22/3:31 posi car. The original engine was gone when I bought it, but it still had the matching # M22 in it which should confirm its SS454 heritage. Anyway... This car has a 6500 redline white lettered tach in it. I know there were no '71 LS6 Chevelle/ElCaminos or 396/375 horse made, so why was this tach installed? Some people have told me they were just leftover tachs for the planned '71 LS6, but I just cannot see GM dealing with that warranty nightmare that might come from someone twisting a hydraulic liftered 454 to 6500 RPM powershifts. Is there anyone out there that might be able to answer this? Has this been discussed before?