Need help ID'ing the year of a 455 block

I have a block with a casting number of 1241735 but that can be any where from a 73-76. It was painted blue but may have been repainted. I have looked between the 5 & 7 holes and the right side of the block for a vin number but nothing is there. Could it be a replacement block. It has the loop cast in the back and a number 5 by the casting numbers. The timing cover is perfect except I put a hole in it by the front abouve the oil pan with a screw driver trying to keep the crank from turning while removing the balancer bolt. I hope I can weld this up without a problem.
Thanks for your help

 

Could be a 72 block but more than likely a 73-74 replacement block.

 

Wrong hole. Look between the first 2 plugs on the drivers side or on the front of the engine.

 

Is the VIN not stamped on the front of the block (benhind P.S.) after 1971?

 

I would guess most its most likely a 73-74, possibly 72.

The 75-76 should carry a different casting number since this block is a different casting. These are supposed to be stiffer blocks. They also have an oval-shaped hole in the deck surface for coolant flow rather than the round hole of the earlier blocks. That's why the trouble running older heads on the newer blocks.

 

pic of number on block

This is the only number I can find on the block. It is on the drivers side back by the back 2 plug holes. Thanks for the help.

 

AF is a 1975 block...205 HP...7.9:1 comp.

 

Thanks Korrie

Any reason there are no vin numbers on it? Could it be a replacement block?
Thank you again to every one that helped.

 

VIN is stamped on the front of the block....just behind the Power Steering pump.

HTH

 

Its not there

I have everything off the motor. It just a bare block now and it doesnt have a vin? Thats why I think it maybe a replacement block? o No:
Thanks

 

Here's a page with the two-letter codes:

http://www.buicks.net/shop/reference/engine_ident_63_75.html\

 

Ed,

I do believe AF is a '75 motor.. I don't believe a letter code was used after 75..

And the vin is stamped on the front of the motor, on the machined area where the timing cover is located, but it's outside where the timing cover is located, on the machined area that sticks out on the passenger side front of the block, right about where the water pump would be, height-wise.

It's stamped vertically.

All motors after the mid year '72 change had the "1735" casting number. 75 and 6 blocks are identified by the vin code, or the "455" cast in the block, near the starter.

 

Thanks Jim

You showed me the vin on the 76 block that you are building for me but this one doesn't have a vin there in the front. Well at least I know its a 75 or 76 block. :TU:
Thanks again

 

A '76 455 is coded SA or SB (California). Think the SB was stricter emissions hence the "California" moniker.

350 engines in '76 were coded PA PB PC PD PK PL PM PN PR PS PT & PU

 

found the VIN!

It is a 75 since it has a 5 in it as the 2nd number.
Thanks everybody

 

If it has AF next to the dipstick hole, then it should be a '75 big car motor. There should be a vin stamped on the right(passenger) side face of the block next to the timing cover on the machined surface. If it has AF on it, it should have a vin. I don't believe that replacement blocks had the application letters on it (AF). It wouldn't have mattered. I could be wrong, but it doesn't seem logical. The second digit on the vin in this photo shows a '5 which is the year '75. It's also an AF block.