Thanks for looking guys- your comments and input are much appreciated.
I really know very little about the originality of this block. I acquired it many many years ago and only know (for sure) what the casting
numbers tell me.
I have had some interest, explainations and feedback to this engine post and the following is only speculation.
I want to be clear that I have not or will not mis-represent what is here, as I do not know anything for sure except that it is a very buildable block and crank and that it is a 3720991 block.
If the engine has no value, I guess no one will be interested.
I am not a knowledgeable Chevy guy as far as engine ids and years and I could not find any information that shows that a 3720991 block was available in any 57 vehicles. That is why (with the stampings on the front and the head dates of May 56) I assumed it is a 56 block.
It was explained to me that, because they did not make a 3720991 block for 57, this must have been a service replacement block. There would have had to have been a number of blocks cast in 57 as warranty or "service replacement blocks" for 56 cars. Dealers that did the warranty work would have had to stamp the block (on a blank pad) at the time of the replacement block being installed. You would assume they would stamp the replacement block with the same numbers as the original block.
Just food for thought:
Lets say a guy cracked a 56 block in early 57 while the car was still under warranty- what would the dealer replace the original block with?
As that was explained to me it seemed to make sense but I really have no idea.
I don't know its history, I only know what the numbers tell me.
That is why I clearly posted the block casting date of D237 or maybe B237.
The heads that came off of this engine were #3731762 dated E106 and E76.
The pictured valve covers came with the engine and heads.
Given what I don't know, does this block have any value?
Thanks for reading.