Help decoding 1965 Impala ss block - Impala Tech
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post #1 of 6 (permalink) Old 07-30-2014, 03:18 PM Thread Starter
Join Date: Jul 2014
Location: Washington
Posts: 2
Help decoding 1965 Impala ss block

I have a 1965 Impala ss 327 with powerglide. I am having trouble making sence of the engine casting numbers and stamped number.

What I have so far:
Cast number (back driver's side) 3782870= 1962-1967 327
Cast date (back passenger's side) D308= April 30 1968?
Stamp (front passenger's side) F0503S= flint May 3rd (not sure on the "S")
Heads 3782461= 1962-1967

What has me confused is the "s". I found that suffix S is for 1962 passenger 327's. And that block castings seem to contradict themselves 1962 to 1967 on one side, then 1968 on the other.

Pretty sure I am reading something wrong here. Any help would be greatly appreciated.
joshtee is offline  
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post #2 of 6 (permalink) Old 07-30-2014, 05:57 PM
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Welcome to the Team Josh!

A 327 PowerGlide with a four barrel would have an HC in the application code stamped on the ledge just below the passenger side head. The other codes used on a 327 in 1965 were HA, HB, and HD. The HB and HD were found on 300 horsepower 327 and the HA on a 327 250 horse manual four barrel motor.

The application code on the front of the motor tells you what it was installed in and with what tranny across all years (they are all fairly unique by decade).

Big Dave
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post #3 of 6 (permalink) Old 07-31-2014, 12:03 AM
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I wonder if that casting date could be a 5, not an 8? Some of those castings are pretty ugly, and a 5 could look like an 8.

It would sure make sense if it is.
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post #4 of 6 (permalink) Old 07-31-2014, 07:01 PM Thread Starter
Join Date: Jul 2014
Location: Washington
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Dave, thank you! Just started working on this car, again, so finding this forum is a blessing.

Darth, maybe you are right and that there might be something I misread on the back passenger side. I'll recheck that. Maybe use some putty to get a good impression of the numbers. Thanks for the help!
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post #5 of 6 (permalink) Old 07-31-2014, 09:16 PM
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That's a 64 327 I believe
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post #6 of 6 (permalink) Old 08-07-2014, 11:47 AM
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Location: Northeast, US
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The cast date of D308 is probably really D303. My guess is the block started out as a '63 250hp 327 with a powerglide according to the S suffix. Someone added the 300hp heads.

Verne Frantz is offline  
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