The easiest way to ID a 428 is look at the flywheel or flexplate. There will be a counterweight on it. Only drawback is the 410's also have the counterweight too. (390 block/428 crank = 410) CJ heads are easy to id using the casting numbers between the center spark plugs. The engine code in the VIN will be useless, as already been pointed out, no 428's in 67 Stangs. Could be a 390 car though, 5th digit will be a "S". 68's also had a 390 2 bbl option, don't recall the letter code though.