Original Engine or not?
 

How do i check if the engine is original to the truck i have please? it's supposed to be a 400 ci. I thought it was a replacement but now is see it has been repainted blue over the chevy red. Where is the engine number exactly and how do I check it to find out?

Re: Original Engine or not?
 

Look at the passenger side valve cover. follow this forwards to the front of the truck. Now, keep looking forward down the front surface of the valve cover. Keep looking downwards onto the front of the passenger cylinder head. follow the front of the cylinder head down to where it meets the deck surface of the engine block. There is a small pad here that sticks out from the front of the block which if you clean the gunk and grime off will be stamped with a partial vin number. If the numbers match the sequential numbers at the end of the vin on the truck, its original.

If the engine was ever rebuilt, and they had the cylinder deck surface milled, the numbers may be gone, but its pretty rare for that to have happened....

Re: Original Engine or not?
 

Great information thank you.

Re: Original Engine or not?
 

Look around here too, lots of good reading:

http://www.nastyz28.com/decode.php

In case it doesn't match your VIN you can de-code to see what you do have...kinda fun.