Was it born a Big Block.

[Karl K.]

Hello everyone,
I am trying to figure out if a 66 vette vin #194376s120321 started out life as a Big Block. The casting date on the block is l 14 5, it think that is December 14,1965 the vin is stamped correctly on the stam pad (I can send pictures) and the other letters and numbers are T033IIP it think the engine assembly date is March 31. Some one told me that there are some differences in the rear end to distinguish if the cart started out as a Big Block. Any help is appreciated.
Thanks,
Karl.

[Joe L.]

Re: Was it born a Big Block.

Hello everyone,
I am trying to figure out if a 66 vette vin #194376s120321 started out life as a Big Block. The casting date on the block is l 14 5, it think that is December 14,1965 the vin is stamped correctly on the stam pad (I can send pictures) and the other letters and numbers are T033IIP it think the engine assembly date is March 31. Some one told me that there are some differences in the rear end to distinguish if the cart started out as a Big Block. Any help is appreciated.
Thanks,
Karl.

Karl-----


The differences in the "rear end" that others are likely referring to are the stub axles. For 1966, all small blocks used stub axles with U-BOLT retention of u-joints. All big blocks used nodular iron caps with standard hex head bolts for u-joint retention.

Another difference relates to the rear sway bar. No small blocks were originally fitted with a rear sway bar. All big blocks had the bar.

Of course, either of the above features could be added to an original small block car to "mimic" big block configuration.

[Karl K.]

Re: Was it born a Big Block.

Was I correct in how I deciphered the numbers and codes and could this be the original engine for the car?
Thanks,
Karl

[Joe L.]

Re: Was it born a Big Block.

Was I correct in how I deciphered the numbers and codes and could this be the original engine for the car?
Thanks,
Karl

Karl-----


If the casting date is "I 14 65" that decodes to September 14, 1965. The engine assembly date of "T033IIP" decodes to March 31, (1966). This puts the engine assembly date more than 6 months after the engine block casting date. That's unusual, but not impossible, especially for a big block.

Your car, the 20,321 1966 built, was built in very late April, 1966. So, the block casting date is well outside the NCRS/NCCB "6 month rule". However, it's possible it's legitimate. Still, you might very well face a challenge in judging.

Could it be the original engine for the car? Yes, it could be, but it's also possible it's not. A detailed examination of the block stamping by someone like Al Grenning might shed a lot more light on the issue.

[Steven S.]

Re: Was it born a Big Block.

Typical span between engine block casting and assembly dates that I have observed on alleged original examples (1966 427's) have been 1 month. The span on the car you are describing throws up a red flag in my opinion. Proceed with caution.

Steve

[Philip C.]

Re: Was it born a Big Block.

Hello everyone,
I am trying to figure out if a 66 vette vin #194376s120321 started out life as a Big Block. The casting date on the block is l 14 5, it think that is December 14,1965 the vin is stamped correctly on the stam pad (I can send pictures) and the other letters and numbers are T033IIP it think the engine assembly date is March 31. Some one told me that there are some differences in the rear end to distinguish if the cart started out as a Big Block. Any help is appreciated.
Thanks,
Karl.

Hi Carl my 66/425 vin 19087 orig block, cast mid jan 66, assy first week of april just an example for ya. Phil 8063

[Wayne M.]

Re: Was it born a Big Block.

.... The differences in the "rear end" that others are likely referring to are the stub axles. For 1966, all small blocks used stub axles with U-BOLT retention of u-joints. All big blocks used nodular iron caps with standard hex head bolts for u-joint retention.

Another difference relates to the rear sway bar. No small blocks were originally fitted with a rear sway bar. All big blocks had the bar.

Of course, either of the above features could be added to an original small block car to "mimic" big block configuration.

Backing away for a moment from our unhealthy fixation with engine casting dates and assembly dates , here's some visuals to go with Joe's stub axle comments (heck of a lot easier to see than the casting date by the starter on a '' BB ).

First pic of small block differential with yokes having U-bolts to attach the half shaft; on the right I'm holding the stub axle from a '65 big block car, showing the caps and bolts.

2nd shot is of rear sway bar on a '65 BB; 9/16" dia. and straight across (ie no off-set bends) on the horizontal part. Same for '66 and '67.

Another easily checked item is the front sway bar; 7/8" diameter on standard BB suspension, or 15/16" on F41 heavy duty suspension, available only on L36 or L72 in 1966 MY. Hard to measure such minor diameter differences; better to wrap a tape around, mark a common line that crosses both tapes; remove tape and measure the length between lines, then divide by 3.14, to get a more precise diameter. If the sway bar measures only 3/4", then it's the small block type.

As Joe says, all the above can be added, although getting the bolts welded inside the frame for the rear sway bar bushing bracket can be a challenge .

[Richard M.]

Re: Was it born a Big Block.

I have 66' VIN 20310 according to the POP the original engine date was T0418IL. I also have the original block from VIN 18241 with date T0322IL.

[Jaime G.]

Re: Was it born a Big Block.

My original motor 1966 BB coupe is vin#18154
Engine casting date A 25 6 Jan 25, 1966
Engine assy date TO 325 March 25, 1966
Body build date H01 April 1. 1966

Its only a guide, but you will see the pattern developing.
Al Grenning can help you.

[Ronald L.]

Re: Was it born a Big Block.

My 427 20533 has a block date of Feb 2 66.

And while it was 32 years ago, the 427/390 I had back then, 70xx, had the same kind of date differential of about 3 months casting date ahead of the actual build of the motor then car.

[Joe R.]

Re: Was it born a Big Block.

Karl,

What is the casting number on the block?

Joe

[Mike B.]

Re: Was it born a Big Block.

My '66 427/390hp block casting date is I 22 5 (Sep 22, 1965) and engine pad date of TII26IL (Nov 26, 1965) with VIN #7216. Like Ronald's L36, there's over 2 months between foundry and assembly dates.

Mike

[Joe L.]

Re: Was it born a Big Block.

My '66 427/390hp block casting date is I 22 5 (Sep 22, 1965) and engine pad date of TII26IL (Nov 26, 1965) with VIN #7216. Like Ronald's L36, there's over 2 months between foundry and assembly dates.

Mike

Mike------


For big blocks this sort of time lapse between casting and machining/assembly is quite common. Keep in mind that big blocks were manufactured in FAR fewer numbers than small blocks. That may have led the Tonawanda foundry to cast them up in batches from which the co-located engine plant drew from as needed.

[Cecil L.]

Re: Was it born a Big Block.

Karl,
I would take another very close look at the casting date. You said it was l-14-65, but thought it was December. It looks to me like you typed the small letter "L (l)" which most interpreted to be a captial "I" for September instead of "L" for Dec.. If that is the case, you should be in the ballpark. The casting dates on the big blocks are notoriusly poor in casting clarity.... at least most of them that I have looked at were. L-14-65 would be a lot more realistic for a March assembly date.

[Richard M.]

Re: Was it born a Big Block.

The replacement block that I located for my 66' L36, has a casting date of
B 1 6, pad date is TO322IL, VIN # 18241.