'88 GMC 1500 Question...

[Will]

My grandfather left me his favorite truck when he died. It's a 1988 GMC Sierra 2WD. It came stock with a 350cid motor. However at some point he had the engine replaced. I don't have enough knowledge to distinguish by eye if it’s a 350 in there or a 305 or what? How can I tell what size motor I have? Are there any markings or numbers?

 

 

Thank you.

[Friz]

Look on the front of the block, passenger sid, by the timing cover. There is a "flat spot" on the block with a series of numbers and letters on it. That is your engine code.

I don't have my book handy right now, but post that code and I or someone else will get back to you with the displacement and year.

 

My guess would be that he replaced it with a direct stock replacement. Although a 305 would fit and probably run okay, it may throw codes to the computer due to a different fuel consumption. I'm not sure about that, just guessing.

I am a non-computer mechanic! One of these days I'm gonna have to get with the times...

[Will]

Got it!

 

There are two sets of numbers:

 

K0610FBC

 

CH7177067

 

So what do I have?

[Friz]

I looked in my book, but unfortunately, my book is not new enough to decode.

Sorry. Someone here has the info - give it a few days.

[99-2door]

block numbers usually don't have letters in them

 

Check again to make sure you have the right number, then go to

 

www.mortec.com

[snoman]

block numbers usually don't have letters in them

 

Check again to make sure you have the right number, then go to

 

www.mortec.com

 

<{POST_SNAPBACK}>

 

 

 

They used to cast block types into the block surface on drivers side in rasied letters behind head next the bellhousing. Have you checked the option codes on the truck?

[Will]

I got the answer from the horses mouth. I supplied the numbers to GM and they said it was a 1987 350cid. Thanks for all the input guys.