Quote Originally Posted by afanoni
Okay, I am not an expert, but I thought I did everything right when I bought a 1966 thunderbird with all matching VIN numbers (6y81q138432). The car had a blown head gasket so I took the heads in for re-working. The machinist told me they were 390 heads. That started a sinking feeling that something was wrong. So upon looking at the engine cast: "C6ME-", I called him with that and he told me that in looking that up the book says the cast code was for "all Ford Engines EXCEPT a 428" Is there anyone who would agree with this machinist? I am very discouraged as I paid a higher price for the car for a Q code engine. Many Thanks.
You probably still have a 428 in the car. Early 428 blocks were C6ME-A like you said but its not a cj block. CJ blocks are usually C7ME or C8ME no big deal its just not worth the money a CJ block is worth but it'll take just as much abuse. The crank is really the only thing that makes a 428, 428cj, or 428scj shortblock anything special. 390's can usually take a 428 bore and then you just slap in the 428 crank and boom you have a 428. I say pull the pan and see if the crank has 1U stamped on it. If so you have a 428 crank just about the only real gold from that motor. Depending upon the 390 heads it has you might have poor man CJ heads. The casting number will be C6AE-R's, and these motors usually have 390GT intakes on them they have a big S "welded" on the runner. No real value in the 390 intakes as they cost more to ship than they're worth, but its a decent factory manifold. It just weighs about a ton. I hope you bought this knowing it was going to basically be a bored 390 with a 428 crank and not a 428 cj. I've owned about 4 of these 66-67 Merc's/t-birds with plain 428's in them that i got just for the 428.