Block

The heart of it all. The block. Casting numbers on BOSS 302 blocks should be C8FE-6015-B for 1969. We have heard of C8FE-6015-B used on very few early 1970's. We have heard of D0ZE-6015-A used for a few late 1969's. D0ZE-6015-B or C for 1970. Ford did make ONE prototype 1971 BOSS 302 Mustang and then the 1971 program was canceled. The D1ZE tooling was already cut so D1ZE-6015-B was used for service blocks. Not only was the D1ZE-6015-B utilized as a service replacement block, but additionally the D0ZE-C and the D0ZE-B were used for service as well for the '70 Boss, depending on when the replacement took place. The C8FE-B Tunnel Port blocks were also utilized as service replacement blocks in 1969. There are "urban legends" out there that suggest there are other BOSS 302 blocks with part numbers C80E-6015-B and C9ZE-6015-A or B. We are not aware of any in existence. But, never say never. If you have one, let us know and we'll re-write this again. If you are looking to replace a block and numbers matter to you then the key is to look at the part number and the date code on the block. Use a block that is date coded before the build date of your car. We frown on V.I.N. stamping a replacement block and it just might be illegal.
Model Year	From the Factory	Service
1969	C8FE-6015-B	C8FE-6015-B
late 1969	D0ZE-6015-A	D0ZE-6015-A
early 1970	C8FE-6015-B D0ZE-6015-A	D0ZE-6015-A D0ZE-6015-B D0ZE-6015-C
1970	D0ZE-6015-B D0ZE-6015-C	D0ZE-6015-B D0ZE-6015-C
thereafter		D0ZE-6015-C D1ZE-6015-B
Note the BOSS 302 block features in this photo. Four-bolt main bearing caps, screw-in freeze plugs. Also note the location of the casting numbers hidden by the starter when completely assembled.