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Discussion Starter #1
Hello everybody

I have a YT engine in my 67 gto.
The number stamped on it is 4241YT it is dated b21..(?!)
As far as I can tell this engine originates from a 67 firebird ( auto) .
So far so good, but on the passenger side ( rhs) cylinderhead , at the back face the number " 48348" is stamped. Does anyone knows what this number means?
Thank you in advance
Arjen
 

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Hello everybody

I have a YT engine in my 67 gto.
The number stamped on it is 4241YT it is dated b21..(?!)
As far as I can tell this engine originates from a 67 firebird ( auto) .
So far so good, but on the passenger side ( rhs) cylinderhead , at the back face the number " 48348" is stamped. Does anyone knows what this number means?
Thank you in advance
Arjen
Pontiac used two letter block stampings that were sometimes repeated on other years, so not the best way to ID the block/engine.

Look at the water pump/timing cover. 1968 and earlier used 8 bolts. 1969 and later used 11 bolts.

Don't think b21 is a date code. Did you find it at the back of the engine next to, or near the distributor hole?

Unknown what 48348 is, maybe the head part number. Heads typically have a 2 or 3 digit casting code on the center exhaust port for easy identification. Looking at the driver side head, you should see a cast date code just below the valve cover near the back of the head.
 

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Like PJ said, find the date code back by the dist, as well as the bock casting number. The casting number was by the dist hole on some earlier engines, and on a pad, below the rear end of the passenger side head, on later engines.

You can plug in the numbers you find & get a better idea of what engine the block was used in.

Wallace Racing's Pontiac Engine Search

The '67 YT code block was casting #9786133 , had 670 heads, and was rated at 325hp.

But the YT code was used on various 400's thru '78, as well as a '66 421.

In your case, the block casting number is critical, because YT was used on some "557" blocks, which could have a date code ending in 7. A block cast in '67, should also have a date code ending in 7. That number represents the last digit of the year in which the block was cast.

If this is true, then I suppose a date code of B067 could mean that the block was cast Feb 6, 1967, OR Feb 6, 1977. The casting number would quickly tell you which year is correct.
 

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Discussion Starter #5
Like PJ said, find the date code back by the dist, as well as the bock casting number. The casting number was by the dist hole on some earlier engines, and on a pad, below the rear end of the passenger side head, on later engines.

You can plug in the numbers you find & get a better idea of what engine the block was used in.

Wallace Racing's Pontiac Engine Search

The '67 YT code block was casting #9786133 , had 670 heads, and was rated at 325hp.

But the YT code was used on various 400's thru '78, as well as a '66 421.

In your case, the block casting number is critical, because YT was used on some "557" blocks, which could have a date code ending in 7. A block cast in '67, should also have a date code ending in 7. That number represents the last digit of the year in which the block was cast.

If this is true, then I suppose a date code of B067 could mean that the block was cast Feb 6, 1967, OR Feb 6, 1977. The casting number would quickly tell you which year is correct.
Big d
The casting number is indeed 9786133 !
Other than that no more news. But I love your responses!
 
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