When did the production of 321 blocks begin and how many months were they cast? Why would GM use the 4 bolt version in 400hp applications (this is not a HP engine)? What is the latest known VIN having an original 321 block? Did early '68's receive any other block, or were the 321 early, and 439 late the only blocks used? Thank you, G.
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Re: 321 blocks
George-----
I would say that the '321' block very likley began being manufactured in August, 1967. Keep in mind that the '321' block used the spin-on oil filter. So, I doubt that it was used on any 1967 year models (although some early 1968 models did use 1967 engines). In any event, I would say that it's a pretty safe bet that manufacture of the '321' began ABOUT August, 1967. The block was manufactured until ABOUT January, 1968. So, it was produced for ABOUT 5-6 months.
I do not know why the L-68 used 4 bolt mains. In fact, I'm not sure that all of them did. But, GM was pretty much free to use 4 bolt mains whenever they wanted to, SHP or not. I expect that there may have been some "advertising-related" reason that this occured.
I have no idea regarding what the last documented VIN was for a car using the '321' block.
As far as I know, only the '321' and '439' blocks were used for 1968 Corvettes with big block. It's possible, though, that some VERY early 1968's used the GM #3904351 block. I don't know if it's ever been "documented", or not.In Appreciation of John Hinckley -
Re: 321 blocks
Thanks Joe, this is pretty much what I had read, but people on this Forum usually have more info than found through regular channels. I have seen several "H" 321 blocks that were in Vetts as late as 6000, so I thought that the earliest casting could have been as early as June or July? G.Comment
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Re: 321 blocks
George-----
I wouldn't rule out the possibility that they were cast as early as sometime in July, 1967. I would really doubt any earlier than that.In Appreciation of John HinckleyComment
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how many 4 bolt blocks?
are you saying all 400 HP engines used the 4 bolt mains or just a few oddball ones? I had a 439 block cast March 1968 that was from an "IO" engine and was 2 bolt main.
MarkComment
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Re: 321 blocks
Joe, apx. how many blocks would have been cast per shift/day? Thanks, g.Comment
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Re: 321 blocks
George-----
That I do not know. Even if we knew that, I don't think that one could extrapolate and estimate how many blocks were actually produced. That's because the foundry likley produced different blocks during the course of any given day and they may not have produced a particular casting number block during every day of foundry operation. To come up with any meaningful production numbers one would have to have foundry production records. I don't know of a source for these for the Tonawanda foundry.In Appreciation of John HinckleyComment
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Re: 321 blocks
Ohay, thanks Joe. The reason I ask is because I have seen H '67 321 blocks up to serial # 6587 which could indicate a large number of these blocks being cast at the beginning of foundry production; and then maybe the foundry produced "as needed" through out the remainder of this short run of 321 castings? G.Comment
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