"-440" vs "-272" Block for 1969 SS 396

[EdEstabrook]

I am in the process of acquiring a '69 RS SS396, 4-speed.  The Trim Plate on the firewall indicates that the car was built in Norwood during the third week of September, 1968.
The 396 cu in., 350 HP, steel crank, two-bolt main cap,  "-272", L34 engine is currently out of the car. The engine code and vehicle code were removed from the block when it was decked during a rebuild. The owner readily acknowledges that this engine is not the original one to the vehicle. 
Jerry MacNeish's book, "The Definitive 1969 Camaro Fact Book" (page 135) states the following:  Camaros manufactured between September and November of 1968 had "-440" block castings.  This was due to a surplus of "-440" blocks manufactured between February and August of 1968.  The casting of "-272" blocks in Towanda did not start until September of 1968.
Upon acquiring this vehicle, I'd like to install an L34 with the correct engine build code.  So I'd like you to confirm here that this car MUST have originally had a "-440" block installed, i.e., it is NOT POSSIBLE that this vehicle originally came with a "-272".  Assuming that is the case, I want to locate a "-440" block for installation in the vehicle.  I would assume that I should search  for a "-440" block with a engine casting date code in the June, July, August of 1968 timeframe?  Or is it possible that any "-440" block from the February through August of 1968 timeframe could have made it into this vehicle when manufactured in Norwood during the third week of September of 1968?
Thanks, all, very much for your consideration here

[nuch_ss396]

Ed,

A couple of things.  I currently have an L/78 with an early August cast date '272 , so that puts a small hole in the date theory of the '272 block.  BTW, this particular
engine assembly date was mid-february 1969 ( nearly a 6 month date spread ).  This date spread is not normal, but still valid.

I also have an L/34 that has an early November cast date '272 that was in a late November built Canada car.

Technically speaking, either casting number should be correct for your car.  I would however, shoot for the '440 block just to be safe.  You should probably look for
one in the late July, August time frame.  I found a 4-bolt main '440 block on eBay a few years ago that had a mid-August casting date.  I've seen others on eBay as
well, so they are out there.  Expect to pay between $750.00 - $1,000.00 for the 2-bolt main version of this block, depending on the over-bore.

I should ask you this:  Are you looking for a block with the proper casting date & assembly date still stamped & legible?  Good luck on that one!

[EdEstabrook]

Thanks very much for the reply/information.  The fact that you have a 396 (an L78) with an August '68 engine casting code seems to shoot down Mr. MacNeish's statement.  I've got a call in to him now to ask how he came about his information.  I'll keep 'ya posted (no pun intended!) after I speak with him.