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· Registered
500 ci caddy in a custom pickup
14 Posts
I really dont want to get involved in your


however, the link provided by 33tom did indicate that those heads were appropriate casting numbers for 77-79 425s...

moreover, a simple google search for "head casting number 1609423" produced quite a bit of information, including a link from a thread on this site...that confirmed the same info above...

maybe some decorum and a longer delay before the :kick: are in order....this is a friendly site...most of the time.

sorry, I dont know, nor do i care at this point, whether those heads could have been on 500s....but the research does not appear to confirm it.

· Registered
'85 Fleetwood FWD
728 Posts
Your heads may have been installed on a 500 block, or if the block was not identified it may have been a 425 All 472 and 500 blocks have serial numbers ending with 5200.

If you go to that site mentioned, , and look at their 2008 calalog, you will find the "info pages". On the info page # 1 there is mention of the 425 engine and the 423 heads. The 423 heads have smaller ports than the 472 and 500 types, even though on a 500 they may increase comp ratio.

Hope this helps......

· Registered
Cadillac Eldorado Convertible 1974
9 Posts
I have looked at all the cad sites and can find nothing on these heads,If you don't know the answer please dont refur to a site that does not have it.
If you don´t read the tips you get you´ll never find the answer... Open your eyes and don´t write back such an bullshi....

Here is the answer you will find on the Engine ID Link:

Head # 1609423 means:
Year: 77-79
CID / L: 425 / 7.0
Description: T: FI (Analog Port)
Block #: 1609110
Bore: 4.080
CR: 8.2:1
Chamber: 96
Crank #: 1609142R
Stroke: 4.060

That´s enough????

Greetings from Germany... :cool2:
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