They all had the 400 emblem on the deck lid. None of the 68's had traction bars. That was just a 67 thing because of the mono-leaft springs..It's very hard to tell without doing a PHS search...here are a few so-so hints..they're not a for sure thing, but...Check the auto shifter...must be a 3-speed TH-400. if the shift indicator dial looks old and it's a 3-speed auto, thats a good hint..TH400's were only available in "400" optioned Firebirds..If it's a 4-speed, check for speedo cable routing. There should be a hole just above the gas pedal pivot on the firewall and 3 clips going down the tunnel..All "400" 4-speed cars used Muncie trans and the speedo gear is on the right side of the trans..I know..a 3-speed HD was available, but quite rare..Check to see if it has the baffle plates on both sides of the hood latch (unless it's an A/C car, then this is useless). Also, the lower front air dam...Last thing..check to see if the Left rear frame rail is already set up for a Left tailpipe (dual exh) Should be threaded with 2 special studs. If it has 2 regualr holes there, it's NOT a "400" all "400"s had dual exhaust..Thats all I can think of..Anyone else?
