Looking at 70 big block. Requesting help where to verify VIN & engine numbers

[Billy H.]

Found a red 70 big block in very good running condition.

VIN: 194370S410943

Engine cast # on driver side behind cylinder head: 3963512. the online records I find indicate this engine # for 1970 454 is for both 2&4bolt COPO engines.

Anyone send me to the right place to verify these numbers?

[Owen L.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

My old copy of the NCRS pocket spec guide indicates 3963512 is a 454 and in 1970 was rated at 390hp; in '71 both 365hp and 425hp.
The engine pad should have one of these suffixes: CZU, CGW, CRI, or CRJ depending on transmission and distributor.

[Terry M.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

If that 512 cylinder case is four bolt, it is an anomaly for 1970 model year.

[Dick W.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

If that 512 cylinder case is four bolt, it is an anomaly for 1970 model year.

Carry over? I have seen many 512 blocks that were factory clearanced for the additional stroke of a 454. The one that comes to mind was an LS-6 454 for a Chevelle.

[Patrick B.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

The OP didn't say this was a 4 bolt block. All 70 454's are 512 castings as well as some 69 427's. Nothing out of the ordinary is in his description of the car. If he would post a picture of the pad, it will probably show a completely typical engine.

[Billy H.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

this helps. thanks Owen

[Billy H.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

thanks. this helps

[Dick W.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

The OP didn't say this was a 4 bolt block. All 70 454's are 512 castings as well as some 69 427's. Nothing out of the ordinary is in his description of the car. If he would post a picture of the pad, it will probably show a completely typical engine.

I have seen 512 blocks as early as April 69.

[Billy H.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

I'll check into a picture of the pad

[Thomas H.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

If that 512 cylinder case is four bolt, it is an anomaly for 1970 model year.

Hi Terry,

I have a an early 71 S/N 1632 with a 512 case and 4 bolt main.......

Tom

[Terry M.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

Hi Terry,

I have a an early 71 S/N 1632 with a 512 case and 4 bolt main.......

Tom

1971 model year is fine. Note the difference between Model Year and calendar year. I would not rule that out for the 1971 Corvette due to the LS6, even though the production of that motor was later in the model year than your car.

There were 4-bolt 512 cylinder cases in Corvettes in the 1969 model year, so there is no doubt that those cases existed in 1970 Corvette model year, but there was no need for them in the LS5 in 1970 model year.

As Dick W pointed out above, the Chevelle LS6 (not to be confused with the Corvette LS6) probably had a 512 cylinder case with four bolt mains. I was thinking Corvette and failed to back up and look at the larger picture. However, I still stand by my statement you have copied above.

[Dick W.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

There were 4-bolt 512 cylinder cases in Corvettes in the 1969 model year, so there is no doubt that those cases existed in 1970 Corvette model year, but there was no need for them in the LS5 in 1970 model year.

Kermit has a 9289 block, VIN Sept '71 build

[Justin S.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

Terry,
In order to make a 2-bolt case into a 4-bolt case, did they just add the extra taps for the added bolts?

[Terry M.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

Terry,
In order to make a 2-bolt case into a 4-bolt case, did they just add the extra taps for the added bolts?

NO, that would be too simple. There are differences in the cylinder case casting, the most obvious of which is above the oil filter mount. I think someone has photos that will be worth much more than my explanation. There were tapped holes in the four-bolt block just above the oil filter presumably for lines to an engine oil cooler. These tapped holes were sealed with pipe plugs in the absence of an engine oil cooler.

[Justin S.]

Re: Looking at 70 big block. Requesting help where to verify VIN & engine numbers

So that leads me to my next question. Why are the casting numbers the same if the castings are different?