[Jason Hart]

I'm trying to figure out what would be the correct engine codes for my 1970 GTO. The car was an early production vehicle that left the factory around Sept 1969. It should have a WT code block in it. The block would have been cast in 1969, so would the year digit by the distributor be a 9 or a 0? What about he casting number, early 1970 or late 1969? The codes for 69 GTO and 70 GTO 400's are both WT, how do you tell them apart? Simply by the production date? Could a late production 1969 GTO and an early production 1970 GTO have the same block in them?

Thanks,
Jason

[Held for Ransom]

Your block would have had a code like G289 or H099 or I019, something like that. And, a block produced after May '69 would have been casting 9799914. EUN would tell the story on the block further.

[slowgto]

The 1970 has its own casting number 9799914. (1969 was 9790071) The '70 WT block also has a large "70" next to the distributor, in addition to the casting date.


I have a '70 four speed built the third week of Sept. 1969 and the block casting date is H149, which is 8/14/69.

The '70 has four engine mount holes, while the '69 has two. They also started casting the "400" on the sides of the block in 1970.

[Chiefpontiac]

Originally Posted by slowgto

The '70 has four engine mount holes, while the '69 has two.

These blocks have five engine mount holes. Two match up with the previous mounts and three for mounting in the new F-body platform and for 455 use.