the heads are probably both C6AE-U as there is no such thing as a C8AE-U. it is probably just a bad casting that looks like a 6 instead of an 8. next is a 68 engine would never have had those heads. a regular 428 in 68-70 has C8AE-H heads and a CJ has C8OE-N's. there are a couple of other head numbers for 68 but they are rare and only apply to 427 and 428CJ's. if the engine is original then it may not be a 68. be sure to check the date code. it is cast between the oil filter mount and oil pan rail. also note that the block number does not guarantee that the engine is a 428 so if you are using a book like steve christ's to verify the block you may be in for a rude awakening as most printed references are wrong because they copied all the lists from each other. the block casting number you cited was used on 352 360 390 and 428 engines from 66 to 69. hawkrod
Hawkrod
39 Ford Deluxe Coupe
59 Tbird 430
60 Lincoln Premier
(2)62 Tbirds
(3)68 Cougar XR7-G's
69 Cougar 428CJ 4 speed
77 1/2 Ford F250 4X4 w/460 swap
86 SVO mustang
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