Engine Research
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Joined: Jul 2025
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Engine Research
I have an L88 427 that I'm trying to get some research on its value. The block is stamped with 3963512 and the heads are stamped with 3873858. I believe this is a 435/427. I picked it up from a friend that purchased it as a crate motor. I currently have it in a 1979 Trans Am that someone is wanting to buy just as a roller. I may part with the big block but want to see if anyone is looking for these specific stampings.
Any help would be greatly appreciated.
Any help would be greatly appreciated.
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Joined: Oct 2000
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From: Shamong, NJ
The "512" casting block was used from 69-71 for every variation of 427 and 454, and in both 2 and 4 bolt main bearing configurations. The "838" casting heads are 66-67 396 and 427 closed chamber heads. It's not likely the block and heads were ever sold as a complete crate motor assembly.
On the right front of the block there should be a machined pad. If the engine was ever sold as a complete engine, and not just a bare block, there should be a series of letters and numbers stamped there to identify how the engine originally started life. The format will be a "T" for Tonawanda, four numbers for the month and day of assembly and a two letter code to identify the engine size and horsepower A block stamped T0213LR would decode as Tonawanda NY assembly plant (T), February (02) 13th day (13) 427/435 with a 4 speed (LR). Of course, what it started life as is no guarantee of what the engine is internally now, especially with a mismatched block and heads.
On the right front of the block there should be a machined pad. If the engine was ever sold as a complete engine, and not just a bare block, there should be a series of letters and numbers stamped there to identify how the engine originally started life. The format will be a "T" for Tonawanda, four numbers for the month and day of assembly and a two letter code to identify the engine size and horsepower A block stamped T0213LR would decode as Tonawanda NY assembly plant (T), February (02) 13th day (13) 427/435 with a 4 speed (LR). Of course, what it started life as is no guarantee of what the engine is internally now, especially with a mismatched block and heads.
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