Identifing big block in my J parting out

["Kelly Pierce" <jkrestor300@xxxx>]

Greetings Group!
The J I am parting out has what appears to be a 383 4 barrel. On the pad it is stamped "T 38", which from all my info makes it a 383. I pulled both valve covers and this is where I am really stumped. It has 6 (six) bolt valve covers, but the heads are casting number 2463200, and have the bolt in style rocker stands, NOT cast in. That casting number is for 63 361,383 and 413's by my info.I have never seen this casting number with the 6 bolt valve covers, every one I have seen has only 4. The block casting is 2128854, my info shows that a 64 casting. I cannot locate a cast in "casting date" on either side of the block. Between the 63 casting heads w/ 6 valve cover bolts and the 64 block casting number I am stumped as to what the heck I have here. The Intake has 2205968 casting number. which shows 62-67 usage, so I figure intakes are the easiest item to change and don't give it much weight in figuring what the engine really is.The carb is a AFB without a pcv fitting, don't remember the carb # of hand. Can any one explain the 6 bolt heads w/ bolt in rocker stands? And/or what am I missing in finding a casting date on the block, or any other info?
Any assistance is very much appreciated. Joe Pierce 300J+Kx3+others 

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