quote:Originally posted by captaintobeys:
I blocks are both D2AE-CA's. The stock block probably needs a little boring, The Boss spec only needs the glaze broken. The Rotating assembly in the Boss motor has been balanced. The other is stock.
Boss 351's were only available on the assembly line. They were never serviced as parts with the same components.
The D2AE-CA is the 351-cj block. Not the original Boss block. It is the "service" part for it yes, but that doesn't make it a Boss part. The Boss balancer, D1ZZ casting number is only on the original complete Boss engine assembly. It was serviced over the counter with the HO blancer which is D2ZX.
That's why when you find the D1ZX balancer for sale separately they are so expensive. They could only have come from an original 71 Boss 351 car.
The original Boss 351 block is a D0AE casting number, not the D2AE.
Smile. The D2AE is the better of the two blocks and you have two of them.
You only need the original casting numbers if you are restoring a '71 Boss 351 Mustang. There were probably never any Boss 351 engines left over from the original build. They just built the cars until they ran out of the engines, then no more.
Ford Service Parts never necessarily gave you the original parts in service. They gave you the EQUIVALENT of them. That definitely is not the same thing.