Conflicting Data

I have a 1979 GMC ?Classic? C15. When I look up/decode the vin on any site it tells me That I have a Big Ten and that it has a 454 under the hood. Here is where the conflicting data comes in, I dont see anything that shows its a Big Ten and it has a 350 under the hood. The emission plate under the hood says the engine is a 350. How do I go about finding out what the factory actually put in this truck and if it is (supposedly) a Big Ten truley? Please Help I am trying to do a COMPLETE restore this information is crutial to accuracy. Thanks

 

reply to your ? hope this helps

Hello there. How many leaf are on your rear diff. If there is only 3 or 4 leafs then some one taken some off or it was not a Heavy 10.
Have you checked the Motor to see if the part of the Vin that stamp on the truck is the same. Here is a link that should help with some the Info.http://www.nastyz28.com/decode.html hope this helps with the vin engine what should be there.

 

I just checked I have 7 leaf springs on each side in the rear does that tell you its a Heavy Half?

 

That would be a heavy half ton rear set up. .
Oh the three leaf set up is very very light duty it is 1/4 ton. So this is not for halling anything that got a little weight to it.

 

I thought that the heavy half came with a 350 SB and there was an option for the 454 BB

 

You could get a 305 W\Heavy Half but most would have been 350 or "454" if you had that motor option that year. the saleman would try to push the 350 to go with the heavy half better motor heaver work.

 

Is the RPO sticker still on the glove box door? That will give you some insite.
Steve