X58

[Loren L.]

In the last 90 days or so, I've asked about Casting # 3748770 that I and others have come across that do NOT have an "X58" cast into them; asked, I might add, without receiving any commentary at all.

You can imagine my surprise when I found, in the first column on page 51 of Driveline #193, an ad selling, in part, a cylinder head with casting #3731539 and a date of G307 AND an "X58" casting!

One of the perceived arguments about +/- "X58" is that this was included only in the first 60-90 days, to call out to engine plant people that this was a changed casting in some way, shape or form and that Flint wanted to know of any perceived/reported changes as soon as possbile.

It would seem possible with this "539" head that another reason for "X58" may be required........

[John N.]

Re: X58

Loren
I have a late 57 770 head with X58.
Regards

[Cecil L.]

Re: X58

I have a set of late 57 539 heads with X58 on them and 2 sets of x58 770s. I'm on the road ight now so I can't check the dates, but I have always wondered the same thing. It would seem that the x58 539's were possibly used on early 58 powerpack engines in cars if not also in early 58 corvettes. Has anyone checked specs like cc's etc to see if any changes in the 770 configuration appear on the x58 539's ?

[Bill B.]

Re: X58

A few years back I sold a set of 056 heads with duel tower symbols castings front & rear and X58 casted just below the exhaust ports that were dated March of 1958. Though they were fuelie heads, I was told they were off a Chevrolet truck.

Bill

[Bill H.]

Re: X58

[IMG]file:///C:/Documents%20and%20Settings/HP_Administrator/My%20Documents/Bill%27s%20Stuff/Car%20and%20Shop/57%20Pictures/Engine%20Details/Front%20Block%20Castings.jpg[/IMG][IMG]file:///C:/Documents%20and%20Settings/HP_Administrator/My%20Documents/Bill%27s%20Stuff/Car%20and%20Shop/57%20Pictures/Engine%20Details/Front%20Block%20Castings.jpg[/IMG]Loren,

Not sure this is related to what you are seeking but here is the front block of my very early 57 -- I have always wondered what the G16 meant -- I surmised it might mean Aug 16 but the cast date is Hxx7 so I discounted that. I have always heard that the intro of the 283 (this was one of the first 283 blocks in the pilot run) was accompanied by some alloy experimentation and the "X" was a heads-up to the machine shop that this was a different part. Someone told me it was to address some cracking problems they were having -- Ken Kayser as I recall it. If you know what the G16 stands for I'd like to know it.

Bill

[Bill H.]

Re: X58

Sorry, -- screwed up the cast date info -- what I meant to say is that the date code is H276. So while I was at it I went back in and got a few more photos of the block with additional unexplained codes (like "H1" in the rear behind the flexplate) that I am hoping some one will decipher for me.

Bill

[John N.]

Re: X58

Loren
I have a late 57 770 head with X58.
Regards

I made a mistake on this post. the late 57 head with X58 I was refering to is a 997.
Thanks