I'm looking at a '70 GS 455 (not Stage I) Owner claims matching numbers. Are the 1970 blocks different markings than the '71-'72? Are the VIN numbers on the side of the block? If not, are they on the DECK? I see where some people say their Block was decked, does that mean the deck has been shaved and the numbers are NO longer visible? Is there a certain casting number on the block? If so, where? Thanks so much. Mac
The vin# on a 70 block is between the first 2 plugs on the driver side on the deck surface and the engine code is between the back 2 plugs on the deck surface. If the block has been resurfaced, the #'s will be gone. They are very hard to find so clean the area real well or you won't be able to see them. You will probably need a good flashlight also. Randy
Got your email. It indeed was this site: http://www.buicks.net/shop/engine_ident.html However, it is still not clear enough. The car that I am looking at has matching numbers on body, tranny, but NO numbers on the engine. The owner claims that he modified the engine and had the block decked (I assume this means resurfaced) he has a new Cam, Heads, Intake manifold, and headers. He seems like a very honest guy, has owned the car for over 20 years. He said the numbers are no longer visible. In 1970 was the VIN actually stamped on the side of the block, or on top where the block meets the head and is not visible unless the heads are removed? Thanks Mac
Mac, If the block was decked, the #'s are gone. The head does not cover the entire deck surface of the block. If you look between the 1&3 sparkplugs and the 5&7 sparkplugs and the exhaust manifolds, you will be able to see a small portion of the deck surface. This is where the #'s will be on a 455. Decking the block removes them.
As usual Larry is right on target. The pic I referred you to is where they would be for a 70 if the block has not been decked (shaved) so as to take them off with the layer of metal removed.
You may have to scrape the crap build up or paint from the deck surface and use carb cleaner or something to help clean the surface. If you get it good and clean and you see machine marks, it's gone.
Thanks everyone :TU: That picture explained it perfect. Just as I thought, numers on a '70 were actually on the deck, silly GM ou: Aside from VIN and Engine code on the deck, if the deck has been shaved, is there any way to determine if it is indeed a block from 1970? Or is this impossible? Thanks Mac
Mac Compare the machined area of the face of the block on the right(passenger)side of the timing cover. The '70 had a 1/2" oil passage and NO ROOM to put the VIN on the face of the block below the lower radiator hose. The '71 and up had a different shape to this machined area. One reason for the VIN stamp which you'll see in the second picture. Two, the oil passage in '71 and later is 5/8" so the face of the block is a little wider. On '71 and later, this area has "V" shape in it above the oil sender unit hole. The '70 block went straight up.
