I just recently purchased a 1966 pontiac Gto.  and I would  like to verify if it has the correct engine and  what  engine it is.  The  number on the front pad is 0104166 YH  the  heads  say 6X on the side,  the  vin # is 6624217  bdy  is pon2663  paint is  E-E  trim  is  219-B   any   help  is appreciated       pat  414-412-7747  or  email lucky_pat53119@yahoo.com  

The YH coded engine you have is a 1978 400 rated at 180H.P. and 7.7:1 C.R. with 6x code on heads.  

The  0104166YH  confused me I  thought the  66  would  be  year  but only YH  motor in  66  was 421 ????    pat  

But the 6X heads are still 70's heads.  Looking at the side of the block, if there is an extra hole for the motor mounts to bolt to then it is a '70's block for sure. I forget the exact cut off year, but the earlier pontiac blocks only had two bolt holes for the motor mounts on the side, in the 70's they went to three.  

Can somebody tell me what engine is in a 1967 GTO that is coded 379123 yf 400 cu. in. hp? HO?  

It is either a 389 or a 400 look on the side of the block and the C.I will be on the side of the block if not look at the back of the block and the 2 large numbers will be the date or there will be a date code on the back of the block. Feel free to P.M me if you want.  

Ny wife has a 77 firebird and the engine code is 004142YA.  I am in Iraq and was going to order some performance parts for her car but I can't seemd to find any information about it. All the info I found was that it was a 350 pontiac engine. Anything else Yall might give me.