Big block codes for 1966 : about 961 and 942.
 

Hello to you all.
I was recently reading an add for an early 450 HP 1966 convertible and a #942 block was stated.
I thought early 450 HP cars had 961 blocks. How about this ?
Many thanks in anticipation.
Best regards
Christian

Our car is a 942 block. I'm pretty sure all of the early L-72 cars were 942.

THanks but I read 'very early' ones had a 961 WITHOUT any explanation about 'very early'...
Best regards
Christian

961 are 396 with a 2 bolt main

Hi
So 961 maybe for other cars than Corvettes.
In 1965 Corvettes got 962, didn't they ?
Or maybe there were 396 with code 961 in very early 1966... That sounds weird to say the least !
Best regards
Christian

961 were used in Chevelles and Impalas. the 65 Corvette 396 used 962 and 208. I never herd of a 961 being used in a 66 Corvette, but then again I am no expert on 66 BB

Ok in fact just to quote my source :
' Corvette Buyers Guide, 1953-1967 ' by Richard Prince

Best regards
Christian

If the suffix 'IP' is not on the pad, it`s not a 1966 L72! :D

Hi

The question I have been looking for an answer for is when and how many were the first 351 blocks used in 66 L72 cars. The fact that there were some does not seem to an issue nor that there were 942 BB's in early 67 as 435 hp models

My numbers matched back in 78 when I bought the car but on a 351 block with a mid march build date. I suppose someone could have done a re-stamp on the wrong block but being as the car had flares back then I doubt if they would have gone to that much trouble for a car that did not even look original.

Doug

The 961 block was used in some early '66 L-36 and L-72's, and the 351 block was used in some very late ones; the NCRS '66 JG will indicate the VIN ranges.

:cheers:

"The casting number for the 427 engine is 3869942. Very early 3869942 cylinder cases to approximately VIN 1700 may have gussets above the timing chain cover like 3855962 (396) cylinder cases."
Quote from NCRS '66 JG; fourth edition. :thumbs:

No other mention of block casting numbers................................



If you are looking for the answer in the judging guide, don't bother. :D

Thanks

You just saved me a few bucks

I was filling out the cc info when you posted that.

Its not like I have plans to sell the car but I was originally told when I bought it that all the #s checked out but years later I was told no go on a 351 block for a 66.

Anyway I am pulling the motor at the end of the week and sticking it in the corner rather than sell it as I had thought of doing if for sure it was not the original.

For sure the one I am putting in is not original :rofl:

Doug

Hi Knight,

Was searching through old posts and found yours. Thanks for this information. I had a look at my very early L36, 390hp 66 and found the gussets on my block. Attaching a photo of the block and also Page 88 of the NCRS JM 5th edition. My car is VIN #269, block casting date of H 20 5, Pad Stamp T0902IL.

Thanks again,

Stevehttps://cimg5.ibsrv.net/gimg/www.cor...6ff132aef7.jpg
https://cimg3.ibsrv.net/gimg/www.cor...70ba3fdd32.jpg
https://cimg7.ibsrv.net/gimg/www.cor...e5096d6b1c.jpg

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Yes they DID use the 961 block in the early 66's. Noland Adams in his book lists about three verified 66's with this block all prior to about S/n 4092. I believe one other has popped up that is correct but not completely verified in the S/n 4200 range. Now what seems to be accepted is that the 961 was a 2 bolt main for the corvette only. So that means that all the 961's were 400/390 eng's. The Sufex codes do not match up with the "Standard" 66 code suffex. but the couple of cars with the eng were verified. The 65 was a 962 block, 4 bolt main, and suffex code "IF" for all I think, but 65 experts may have better info. Now, the two 66's (that we know of) with the 961 blocks were code "LF and IK". Now this is where i am guessing but, makes sense, The 961 I THINK they played with the crank, rods, piston to get the 427 ci..and list it but have found no definitive info to prove it one way or the other and only used them when they ran short for delivery. What I do know is the 961 block is not thick enough to punch out to a standard 427 (942 block) bore. This all gets muddy again at the end of the 66 run with the 351 block.

good luck

Let me throw this into the pot; I have this 3855961 2-bolt engine, cast E_14_5 (May 14th '65) but don't know what it was originally in. This is a deep grind-out and re-stamp (?) dated May 7th.
Seems to have bounced, resulting in ghost image in the suffix area. The right side of the pad is a mix of single digits, some at 90 degrees to the flow.

Notice the nice broach marks.

https://cimg5.ibsrv.net/gimg/www.cor...e099ad94e2.jpg

who knows what Bubba was doing. definitely a re-stamp and way to early for a 66 vette

This thread makes me sad. I see it is very old but on a good topic. I have a '66 VIN 1568 that originally had an L72. Now it appears my early original motor was a rare bird.
I know it had an L72 because in 2002, there was a gentleman named Scott Bonar who posted on NCRS looking for the car that went with his motor that had my VIN derivative. I've spoken to 3-4 people with the same name but none used to have old motors. The trail goes dead after that. I'm looking for that motor! I have posted in the orphans thread.

mine is 1521.. went down the line the same day...

I picked up a 3855961 2 bolt that has been sitting in a barn for 40 years. The gentleman told me it was a 427. Date code is C25 and the Suffix is T0322LF it has a partial vin of 1224826. The bore is at 4.25. I have it at currently at shop being sonic tested. Anyone have any info on 961 427's?
https://cimg5.ibsrv.net/gimg/www.cor...f141bf1851.jpg

It’s a 396/325 out of a full-size 1965 Chev.

I read what Johnz said above about the 961 being used rarely as early 427 blocks, and have also heard the stories of them “playing with bore and stroke to achieve 427 ci with the 961 block”. I think it’s malarkey. What internally balanced crank might they have used?? I wouldn’t touch a 1966 with a 961 block. It doesn’t support a 4.25” 427 bore reliably. Tonawanda had the 3869942 1966 ready for use for the 1966 427’s, and if they had an issue with supply for those, they also still had plenty of thicker wall 396 3855962 blocks available that supported a 427 bore that they were using for the L78 375 hp 396 Chevelles. They had so many of these blocks that they also used them for the L34 360hp Chevelle engines even though engineering only called for the 2 bolt 961 for the L34.
So why would Tonawanda use thin 961 blocks for a 390 HP 427, but use thick wall 962 blocks for a 360 HP 396, at exactly the same time period.
With great respect and regard to John, I personally think the 961/427 is a combination of old wives stories, lies, and wishful thinking for something that never happened.