I have what I think is a 1984z28 but I'am not so sure of the year and engine size(stock) could you help me decode my vin#igiap87h2cni54123 thanks for any help you can offer.

Here's the VIN, using "1" instead of "i".

1 United States
G General Motors
1 Chevrolet
A Restraint system- manual belts
P Line- Camaro
87 Body style-2 dr. coupe
H Engine- 5.0L V8 4 bbl
2 Check digit
C Year - 1982
N Assembly plant- Norwood, Ohio
154123 Sequential build number

This VIN indicates that it's a 1982, not a 1984.