to me it looks like a 51 350. ask him to look on the forward part of the drivers door jamb that is where the tag is if it grosses out at 16000 thn its a 350. it should read something like this 50 300 series 301 or 302 with a 24 or a 51 350 series 351,352,353 with a 24(248 ci) following with sequence #xxxx
301-24xxxx
353-24xxxx