Cleveland engines part 10

For XA GT’s, the switch to square blocks appears to have taken place in May or June, 1972 for automatic trans equipped cars, and in August or September, 1972 for manual trans cars.
As mentioned earlier, the square block seems to have appeared in the U.S. in 1971, as the engine fitted to 1971 Boss351 Mustangs were square blocks, as below.



It is worth noting also that Boss351 blocks were also four bolt main blocks.
Australian manufactured blocks have the letters ‘GF’ cast into them at the rear, upper surface beside the oil pressure gauge adaptor. ‘GF’ stands for Geelong Foundry.



US blocks had ‘CF’ for Cleveland Foundary cast here, and some early Australian cast blocks were ‘CF’ as well as they used the US casting moulds initially.The change from ‘C’ to ‘G’ would have been relatively easy to carry out.