i thought the 85 IROC-Z came with the LB9 package but mine has a 5.7 liter tag???? could it be fake??

 

Yep, sure is. Check your VIN.

 

No 350 in the 1985 IROC-Z28 model. LB9 is the RPO code for 305 TPI engine option ( note it is not a package just the engine code). The eighth digit of the VIN is for the engine code, which for the 305 TPI is the letter (F).

A lot of people put badges on their cars just for the look of the badge like a 5.7 liter.