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Motor numbers


sredmyer

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So I have a few of these gems and all but one are numbers matching.  My most recent acquisition, a silver 1970 SS454 is not a numbers matching motor.  The motor has some stuff stamped on the deck behind the alternator but the only thing I can make out for sure there is the CRN.  From everything I have been able to determine that means the motor is a 1970 454 out of a Monte Carlo.  However, the few numbers stamped on the block by the oil filter that I can read (I can only actually read 2 numbers) do not match the cars VIN. 

 

So the according to the CRN code the motor is a 1970 Monte Carlo.  We all know the only way to have gotten a 454 in a 1970 Monte is with the SS package.  That seems really unlikely that someone would have replaced the motor with one out of another 1970 SS.  Especially considering all the other things about this car which are not "correct".  Is there some other way to explain this?

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Steve, I beleive the numbers in front of the CRN stamping are production and plant markings. Maybe someone can confirm that fact. The vin number on mine is stamped to the right. You could have the original engine block in the car. I added the picture showing my vin. Check out this web site:

 

http://chevellestuff.net/qd/engine_stamp_numbers.htm

post-6465-0-59510100-1534517188_thumb.jpg

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Compared to the 1970mcss picture, sredmyer, it looks to be possibly your block was "decked/machined". I say that due to the cut look compared to 1970mcss. Also how shallow your CRN is. Could be that your vin # was machined off.

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Compared to the 1970mcss picture, sredmyer, it looks to be possibly your block was "decked/machined". I say that due to the cut look compared to 1970mcss. Also how shallow your CRN is. Could be that your vin # was machined off.

That is kind of what I was thinking. 

 

I just wont be able to match this motor to the car.

That's a shame though, I am nearly certain this car is a true high option SS but I do not have a build sheet and without a matching number 454 I just can't be certain.

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One of mine was in the side of driver front seat back, one in the front bench seat bottom above the hump and one under the carpet under the driver side.

I suspect there are more. Mine is a Baltimore produced car.

rob

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The numbers before the CRN would be the date of the block assembly 4 digits, 2 for month and 2 for day which would follow a leading "T" for Tonawanda factory ie. T0313CRN. You can check other engine components for dates if they are GM factory items - like the the intake manifold, distributor and heads if you pull the valve covers. If the stamped dates are before your VIN date month and week, chances are it might be correct.

 

The block itself should be stamped on the top back near the bell housing with 3963512 for 1970 454 and also have a date code stamped nearby for when it was cast that can then be checked against the body tag month and week. "Chevrolet by the Numbers 1970 - 75" book by Alan Colvin is excellent reference for correct part numbers and date codes. Jim

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