Hello have a 1989 camaro RS tbi how can you tell the diffrents between the both engine 305 versus the 350 Im not sure what I have since the brought the car fro a do it your self kind of guy?

 

Casting number on the passenger side bellhousing. some blocks do have the displacement (5.0 or 5.7) on the driver's side though.

 

Post yours, or Google it. It's THE ONLY 100% reliable way to tell what block you have.

 

Visually, they're identical. The casting number as pictured above is one of the best ways. Since the 305 and 350 have different bore sizes, they'll never use the same block casting.

Getting the suffix number off the pad in front of the passenger side head is an alternative way to find out what it is. It can also tell you if the engine is original for the car or not. Casting numbers were used for many years and in many different models.

Depending on the year of the block, there may also be a 5.0L or 5.7L cast into it.