1st block is 3963512. Date is G 13 70. 2 bolt main. Suffix code is CPD. Standard bore.

2nd block is 3955272. Date is 69. 4 bolt main. Suffix code is JD. .040 over.

Let's ID them first.

CPD for 1971 was used in the Impala and Chevelle. LS-5 454 / 365 hp
Seems to be for the TH400 automatic

JD for 1969 was used for the Chevelle. 396 / 375 hp L78 4 speed.

Let's ID them first.

CPD for 1971 was used in the Impala and Chevelle. LS-5 454 / 365 hp
For the Chevelle it was used with the 4 speed.
http://www.chevellestuff.com/1971/engine_id_codes.htm

I think I was wrong above. It depends where you go for the information, but I won't argue with what Dale has posted.

Another site I looked at showed CPD was also used in the Monte Carlo in 1971. That showed it used with the manual transmission on both the Monte and Chevelle. But I now believe it was wrong after a message from Dale M.

Partial VIN would help tell what it was from originally.

I did edit my earlier post. Again.

MSA-1 book shows automatic TH-400 as well, the only reference I found for manual was chevymania.

To answer your question as to value since we don't know if they have been tested for cracks, I will assume they are in good condition. Of course they are worth allot more if someone has the car they go to, but as just rebuildable cores about $600 - 800 for the pair if in good condition. I don't like the ideas that the 396 is .40 over but sometimes that cannot be helped, but still they have good value in my opinion. Just my .02

OK, if there are no problems with the blocks, no cracks or sleeves needed...

I would say 400 each. Maybe more.

The 0.040 over hurts a bit on the 272 block.