I tried the search feature but failed. So was the 961 block really used very early for a 427 application? If not why is it listed as a possibility in all the reference books?
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Re: 1966 427 block usage
This ad was posted online about 1-year ago... along with the pictures that follow:
Selling a rare original gm 66 corvette 427 390 HP motor, std bore, casting 3855961 date I 6 5, code T1006IL vin 6102889, heads 3872702 dates I 2 5, I 10 5, intake 3866948, date L 2 5, holley carb 3882835-E0 list 3370, this was rebuilt 40 thousand miles ago, they put new piston L2300 in it with new stainless valves, need to be freshened up again, customer installed a new 502 motor, this has been sitting for many years. Asking 4000. Call 352216XXXX (REDACTED)
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Re: 1966 427 block usage
So is that stamp pad real? Does anyone have documents from GM or Tonawanda saying they used the said 961 block?Comment
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Re: 1966 427 block usage
Yes, that is the thread with the photos of the 961 block I was referring to. The space between the inside walls of the cylinder viewed through the freeze plug hole in Wayne's photo seemed to be greater than those of the 1965 962 blocks and 427 blocks that I have (which have the same space). That lead me to conclude that even 1965 961 blocks were thin wall blocks. Clearly that is not true for the 961 block in your photos since the L2300F pistons are for a 427.Comment
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Re: 1966 427 block usage
Looks to be a re-stamp to me Phil 8063Comment
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Re: 1966 427 block usage
If it is a restamp, I think it is a very good restamp. If one looks at the photo with that thought in mind, the grain on the pad could be seen as different from the grain under the head gasket. However, that is a hard judgement to make from just the photo. The engine has standard bore pistons that are not original equipment which suggests that the 427 bore could have been done when this block was rebuilt rather than at Tonawanda, and the manifold is not dated with the rest of the engine castings.
This engine is still a bit of a mystery. Too bad because it seemed to answer the question about early 427s.
Philip- what features lead you to think it is a restamp?Comment
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Re: 1966 427 block usage
I see as many broaching marks from underneath the head as not. If it is stamped, it was broached first.Comment
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Re: 1966 427 block usage
The grain of the broach lines on it are continuous straight lines, factory broach lines look more like morse code, line are not continuous. Also seems to have been bored to 427 std size, notices size of valve reliefs left in the deck, they look very small. That would make it seem to have been a smaller bore. (A good looking stamp), but I am not familiar with the #1 after the T . They usually use a capital I for the number 1. I am not Al Greening but my humble opinion. Phil 8063Comment
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Re: 1966 427 block usage
^ those are valid observations alsoComment
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Re: 1966 427 block usage
Good observations, but sometimes photos create optical illusions with highlights and shadows.
Does this zoomed in grain pattern on the SAME pad still appear as continuous?
I also found a similar assembly date... seems they used a weird character that day:
You folks might very well be correct regarding the bore, but we have no knowledge of where/why it was done.
Why are books indicating these blocks were available in early 66 production... where did that 'rumor' occur?
Is there any database of previously judged 66 Corvettes... does the 961 block appear in it?
Just leaving the possibilities open, before I close the door.Comment
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Re: 1966 427 block usage
The "1" character after the T that differs slightly from the more common "I" was the reason the stamp first impressed me as authentic to Tonawanda. It appears in lots of 66 and 67 427's. It is really interesting that you found another Oct 6 390hp 427 and the character mix was identical.Comment
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