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1965 Impala SS 396 Convertible
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Discussion Starter · #1 · (Edited)
Hi all. New to the forum! I just purchased a 1965 SS 396 at auction. VIN confirms it is an original SS, but not sure how to tell if it is the 325 HP version or the 425 HP version. Did not have the opp. to talk to the previous owner, so no provenance info. Has a TurboHydramatic if that helps. I heard that the 425s all came with manuals, but not sure if that is true
Vehicle Car Hood Automotive design Motor vehicle
 

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Let us have the Engine Suffix Code on the Front Pad of the Engine.
 

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Also, to be sure it's unmolested once you know what it's supposed to be, remove a valve cover & decode the cylinder head #Part No. There's a good reference Here for Cylinder head I.D.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #5 ·
Great! Thanks for the info. Removing the v/c's is pretty easy on this thing (at least access is good - depends on how much gasket **** the last guy used!)
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #7 ·
I couldn't locate any numbers on the front of the engine. Can you give any guidance about where they might be? Perhaps on the manifold? It has a replacement Edelbrock , not the original one,
 

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From memory looking from the front of the car, if you look below the l/h/s cylinder head there's a flat surface on the block with your engine numbers.
 

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Looking at it, it is the Left Side, but it is actually in Front and the Bottom of the Passenger Side Head. It is actually on the block itself, which extends out passed where the head is bolted to it. The pad with the numbers and letters on it is long and narrow.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #10 ·
Thanks! I cleaned off some oil and found the block number behind the driver side cylinder head.

3855961 and the letter P
How to decode?
 

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Thanks! I cleaned off some oil and found the block number behind the driver side cylinder head.

3855961 and the letter P
How to decode?
That's the Casting Number, which a quick search found it to be a '65 to '67 396 or 427.

What we need is the Engine Suffix Code. I'll try to find some pictures for you.
 

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1965 Impala SS 396 Convertible
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Discussion Starter · #13 · (Edited)
Thanks! Found it with your excellent guidance! It had a lot of engine paint over it, so I had to scrape a bit to get the numbers. Here they are:
TII03IVH6D125137
Looks like it is a Tonawanda '66 396 engine that originally came with a Powerglide? Am I reading it correctly? Also where does the VIN portion start? Doesn't really matter but just wanted to know for future ref. None of it matches my VIN! Prev. owner didn't sell it as "numbers matching" anyway, so no foul.
The BBC suffix code link at Chevymania.com is no longer working :( but I found this web page:
Chevrolet Big Block Engine Identification Casting No, & Engine Codes (wowmusclecars.com)
 

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IV is a '65 396/325. You have an IVH and H means Holley Carb. I am not seeing an IVH for a '65 anywhere and you could have a '66 Engine there. Next you need to either find the Date Code or in your case check to see if the 6D125137 matches your VIN Number.


IVH1966396325TH400B, Holley
 

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The Engine Date Code is on the back of the block as also shown in the picture. It can be on the Left Side or Right Side of the shelf. But, is very hard to see with the engine still in the car. If too unreasonable, the next best thing is the heads and that would involve removing the valve cover as mentioned above. But again, that's if the heads are original to the engine.
 

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This is my "go-to" for numbers decoding --> https://impalas.org/
Looking under the "drivetrain" tab, here is what I found:
The carburetor designation, "R" = Rochester and "H" = Holley was only used in 1966.
TII03:
T = Tonawanda, New York engine plant
II03 = November 3rd. Probably 1965
 

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Yes, that is just the way they stamped it --> "I" is a "1".
 
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