Confused about motor is it a 383 or 400

Radical Fred

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I recently removed the motor from my 66 fury3 as I had another 383 built and stroked to a 496 with aluminum heads and intake. The casting on what I thought was a 383 comes up as 3614230 built 9/16/71 and heads are 2843906-11. when I google the numbers I get a 383 or a 400 heavy web block. how do I know which it is?

IMG_20250613_212032 (1).jpg
 
I could be talking out of school but the date of 9/16/71 tells me it is not a 383. By then there was no more 383s being built.

What does it say on the distributor pad?
 
I recently removed the motor from my 66 fury3 as I had another 383 built and stroked to a 496 with aluminum heads and intake. The casting on what I thought was a 383 comes up as 3614230 built 9/16/71 and heads are 2843906-11. when I google the numbers I get a 383 or a 400 heavy web block. how do I know which it is?

View attachment 723909

The pictured engine block with casting number 3614230 is a 400 and with a casting date of 9/16/71 is probably a 1972 400. As mentioned, the pad next to the distributor will yield more information, but should have "H400" stamped for 1972 with other numbers.

Block casting 3614230 was also used in a limited production run of 400-two barrel 1971 Newports, but would likely have an earlier casting date, depending on when 1971 production ended. A 1971 400 will have "G400" stamped on the distributor pad. Reference: Technical Service Bulletin (TSB) 71-9-8, April 13, 1971.
 
Your 1972 400 was Cast September 17, 1971. Look below distributor for the machining date and the 400 stamped there.

They stopped building 1971 cars near end of July 1971



71EAC15A-F46D-4F9B-9F94-1DE9BBE44C0C.jpeg
 
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I recently removed the motor from my 66 fury3 as I had another 383 built and stroked to a 496 with aluminum heads and intake. The casting on what I thought was a 383 comes up as 3614230 built 9/16/71 and heads are 2843906-11. when I google the numbers I get a 383 or a 400 heavy web block. how do I know which it is?

View attachment 723909
It's a 71-72 400 block. 383's ended in 71 and their casting number was 2468130. See the difference in sequence? The 383 castings were around a lot earlier and are a lower number.
 
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Have you had a chance to look at the VIN on the passenger's side? That will help tell us what it came out of.
 
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