Need help with identifying gen 2 block

[Big_Swede]

I need help with the origin of a Pontiac block.

I have looked at a Pontiac Trans AM 1970 RA3 with manual transmission (M21)

Everything with the car checks out except the engine block. When the current owner initiated a restoration of the engine, a crack was found in the original WS block, which was scrapped.
The owner has photo documentation of the engine restoration, which is based on a replacement block. I have spent hours trying to determine where this block originates from, and struck out. Based on the various casting numbers, this block seems to be non-existing, based on several visits on different websites with Pontiac info.

So, maybe you guys can assist me?

The casting numbers:


Casting Code = 9799914. Indicates a true 1970 RA3 block? (It is a 4 bolted block)

Engine Code = YD. According to the websites, no Pontiac YD block with 4 bolt mains?? The Y tells me its from an automatic?

VIN-casting = Above the engine code. Hard to read but seems to be 0040115. Does not match body VIN.

Displacement ID = Have not found any, either on the side of the block or in the lifter gallery. Since it is a 400 block, produced no later than 1971?

Freezeplugs = Three per side

Date stamp = Waiting on info from seller

So, what do you make of this? A 400 block stamped YD with 4 bolt mains and 9799914 as casting code? Is this some sort of replacement block from GM, or what Pontiac did it come from?

I really need some help! Info on these cars are scarce in Sweden where I live

 

[melsg5]

my source tells me a YD with a casting of 9799914 matches only one engine
Year=1970, CID=400, HP=290, Code=YD, Transmission=Auto, CR=10.0, Cam=254,Head Code=16/sm valve, Carburetor=2 BBL, Carb#=7040060/64,Block Casting=9799914. The number of main bolts is causing your confusion and has nothing to do with ID'ing this engine, the caps have holes for the additional two bolts so they can be easily added. It's a low performance 1970 400. Without knowing which heads and cam they used it still could be low performance. According to the April 1983 Parts Catalog the YD code was used for the Grand Prix and large B body cars.