Originally Posted by clevelandpartsguy
this is an old thread but I am talking to a guy about a 70' SR block lately, you mentioned a SR RA iv block. How would we know its a RA iv replacement? for 1970' the 9799915 casting and SR stamping would nail it down right? Assuming the 9915 was used only for RA iv production. what about if its a 9799914 and SR stamp? That leaves it open to being a RA iii or other replacement. Please tell me your expert thoughts on this.
I would agree with your statement if the block also has 4 bolt main caps. In my opinion, a 4 bolt block with 9799914 cast and SR stamp would originally be intended as a replacement for 1970 RA III or standard manual (WT) applications because that block would have originally be machined and fitted with cast pistons.
If your car is a 1970 L67 and you are looking for a replacement engine block, you have several choices the way I see it. Order of preference is subjective....but my priority list would go something like this...(assuming of course the original partial VIN stamped engine is no longer available)
1. Documented 9799915 SR block. NOS, standard bore, with fitted forged pistons, dye marks, SR tag etc. New, never used.
2. Same as above, used. May require overbore.
3. Reclaimed 9799915 block from donor RA IV car. Can be documented by partial VIN and PHS docs. Would need the correct 2 letter code for your application.
4a. Undocumented 9799915 SR block. This would be a 4 bolt block with the 979991 numbers cast and the last digit ground and stamped 5 or could even have all digits ground and stamped. There is a specific font for these digits.
4b. Same as #3
with any of the remaining 2 letter codes
Opinions vary of course. The reason why I place #1
is because a documented SR block COULD be correct for ANY 1970 L67 car. Block #3
is only correct for one specific car. The application is correct for your car but since it has a partial VIN...it really is only correct for that particular car. However....the partial VIN documents it as a L67 application so it would place higher than an undocumented SR block in my opinion.
Block choices 4a and 4b are about the same in my opinion.
I have an undocumented SR block for my 1968 L67 car. Its cast date is Dec 1969 so it was surely a 9799914 casting. That number was ground and stamped 9792506 and has an SR number. Is it correct for my application? Could be. However, it could also have been a 9799914 SR 4 bolt block intended for 1970 RA III or WT applications or maybe a 9799915 block and someone later ground off the numbers and restamped 9792506. Font looks correct but without documentation it is anyone's guess. In my case the engine came with the car when I bought it but that doesn't really prove anything since I have no documentation to validate. It would be nice if someone discovers some sort of tracking log or audit sheet for all the SR numbers for each year. If that were to happen, I suspect it would expose quite a few blocks as altered.
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