Did I buy a 428 and get a 390 Thunderbird?

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.

All is not lost. Checking C6ME list a cobra jet 428 from 1966-70. It also list numerous engines from 352-390. I'm not a ford expert, so maybe others can help.

What are the casting numbers off the heads?


Bill S.

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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.

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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.

but I did not mention too that my husband measured the stroke and it was under 4 inches! (3 and 7/8) Well, we only had a cheesy tapemeasure and not a micrometer. I told the machinist that and he said that is not acceptable to verify. Since I have to put it back together obviously, and make decisions as to re-ordering parts, he wants to be sure he orders the right thing. He will only accept the crankshaft for verification. Also, the intake manifold says C6AE 9425-G. It will become obvious I know NOTHING about engines! I read the posts and can see there is alot of respectable expertise out there, but this machinist seems dead set on his idea too and I a little afraid to challenge him since I don't know anything. That bore measurement convinces my son and husband that I got taken!

NO "A" after the dash mark, it is C6ME only. There seems to be an obvious grind mark after the dash though.

on the intake manifold and it says 390 66 6 6 b 357 S.

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Originally Posted by afanoni

on the intake manifold and it says 390 66 6 6 b 357 S.

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If you found the tag on the engine and it says 390 it sounds like you have a 390. On a side note it sounds like you have a 390 gt intake on the motor worth $50-75.

it seems there are too many things that point to the 390, but does anyone know why the machinist is not satisfied with anything other than a piston and/or a crank number? It seems obvious enough with the stroke measurement and his response to me was: A tape measure is a tool for carpenters and I ain't a carpenter" boo hoo.

I just talked to a person referred to me who is quite involved with T Birds and clubs and all. HE says the Engine block I have C6ME is a Mercury Block and could have a 428 crank in it. He referred to it as a 410. He also says to look for counterweights on the flywheel. And I do NOT like to get under the car because it wrecks my hair and my hands, but what do you think of the other ways of finding out about the block. I guess we are certain the intake manifolds etc.. are 390-ish, but are they built that way? Why would this happen?

Yes they did make 410's which are 390's with 428 cranks but i believe that engine tag would say 410. It seems odd that the car would be originally a 428 car, yet end up with a 410 in it and have a 390 engine tag on it. It could happen but i doubt it. Here is some good info on the flywheel, and they should also have some good crank identification info. The easiest/sure way to find out if its a 428 crank is to pull the pan. The crank is all you're after anyways.

:HMMM: one reason this would happen is a lot of fiddling fingers over 40 years. :confused:

Either way it looks like you are going to pull the motor to do a positive I.D. check.

Its a bit like the theory about eggs in the birds nest, you could surmize all the reasons why there are eggs in the nest, but untill you actually climb the tree and look you dont really know. ;) :D

Sorry i forgot to post the link to the info i was talking about. http://www.428cobrajet.com/id-flexplate.html

Hey, get yourself a 6" dial caliper, whether you have to steal, beg, buy or borrow one. Have someone to bring any piston to top dead center by putting a socket and ratchet on the bolt at the front of the crankshaft that holds the harmonic damper onto the crank. You can stand by a cylinder and keep checking that you are close to TDC on that cylinder by checking with the depth function of your caliper. It probably will never come to zero, because the manufacturer of the piston will have made if to that it will not come to the deck of the block at zero, but make it come as far to the block as possible. When you have TDC, record the reading on your dial caliper from the top of the deck to the top of the piston. It may be 0.020", 0.025", o.030" or whatever. Now, have your helper turn the crank to move the piston to bottom dead center. Move it around a little to be sure you are at BDC. Record that measurement from the top of the block to the top of the piston. From that figure, deduct the figure that you had with the piston at top dead center. For a 390, the stroke will be 3.780", for a 428 it will be 3.980". Good luck and sorry about your hair and nails. :)

Hey guys, how did I do. I clicked those figures off without referring to anything. :)

Oh, many thanks for all that- that is all useful BUT I still have a question! Why is the tape measure of having the piston all the way down perfectly, using a level for the corresponding piston to be all the way UP, inadequate. It is 3 and 7/8 inches at MOST and that is just too far off the requirement of 3.98 inches that even if we were off a little, it is not close enough to feel right about. Does that seem reasonable? That we could squeeze another 1/8 inch? And what about ANOTHER suggestion, that the pistons should have a marking on them that shows they are bored .003 over. THEN another guy said the 6cME is a Mercury Replacement Engine?? Oh, and the last time I got under that car, it is on a horrid driveway on a building site, the weeds in my hair were so frightful my son blew me off with an air compressor and it was equally horrid. He is an engineering student at Seattle U and thinks he knows everything, but I am finding that he is way over confident this thing IS a 390.Too many brains!

O.K., a 390 is 3.780", your tape measure is 3.875" and a 428 is 3.980". You choose. And again, sorry about your hair and nails. I'm just trying to tell you the correct way to do it. I can sympathize with your machinist.

I guess what is being said is: Yes, the stroke measurement needs to be accurate, all agreed. But that asking a micrometer to find almost a quarter inch and not much less is a tall order. I do see your point and it is well taken, believe me and very much appreciated. I WANT to sympathize with him in a sense because I want it to be right- a 428, what I bought. And since I paid just 2200 for the car, it won't be the worse loss I ever suffered. If it has a 428 crank, and a 390 block, I feel the thing to do would be to "correct" the block if possible. Whether that means buying a new one, or boring if needed. I do not want to be annoyance being new at being on a forum, so I try to be intelligent in my questions and refrain from mentioning too those little black crumbs that drop on my face ruin my make up. I was not at all into engines, though my father was a rocket engineer and I married a motorhead biker and after all this time I thought- if you cannot beat them, join them. So I did- IN FULL force, and now I have made a terrible mistake in the car I am afraid!

can i ask why you think a 428 is so imporant? are you going to build a nice motor for it? Are you wanting to build a cj?

and MY favorite machine is a 1922 Steinway model O grand piano. But as I said, I could not beat them, so I joined up. I do find that a scholarly approach to the would be 428 Thunderbird project is needed. The "engineers" around here are a little quick to write it off as a 390, I shall continue to enlist the help of you all if I am to be included- again with many thanks!

"or boring if needed"

I don't think you have enough cylinder wall to bore a 390 to a 428. The 390 is 4.050" and the 428 is 4.130". That's 0.080" worth of overbore and I think you would have overheating problems due to a too-thin cylinder wall. But, that's just my opinion. Sorry about your hair and nails and those little black crumbs that drop in your face and ruin your makeup. I hate it when that happens.

By the way, does the block have vertical "ribs" running from the deck to the pan rail. I forget how wide they are, maybe a half inch wide and just maybe one sixteenth high?????

"I shall continue to enlist the help of you all if I am to be included- again with many thanks!"

YOU GO GIRL!!!!!!!

I am an old Ford fan recently converted to SBC thinking so it is great to see the Fordnatics come forth with tech stuff. It seems to me that "afanoni" is a lady who writes well and she is to be encouraged, I can't get my wife into the garage unless it is to look at some clean new piece of stainless beauty and I catch a lot of heat if I don't wipe my feet coming in from the garage, so I can understand why she might not be receptive to a relatively easy process of pulling the crankcase pan. That is surely an easy but quite dirty job. Still why be upset over a repairable T-bird that only cost $2200? That sounds like a good deal to me if there is minimal body rust. If it is a 410 and you can clean it up, get it painted and fix the interior and enjoy it. I don't understand the difficulty of micing the bore depth, the local shops I used to be familiar with would send a guy with a few different micrometers to any garage contemplating an engine build to at least indicate out-of-round cylinders and what is so hard about finding a depth gauge micrometer? It should be possible to find a shop that will do this for a very small fee and your mechanic should know who to call? So why not pay the mechanic to pull the pan and ID the crank or find someone with a depth micrometer?

Don Shillady
Retired Scientist/teen rodder

Well said Don. Any self-respecting hot rodder with a dial indicator could identify that beast in just a few minutes.

I can understand the hair and nails deal, couple weeks ago I forgot to tuck my ponytail inside my shirt and got it tangle up in the creeper wheels!!!!! Hair fires when welding have always been a problem!!!!

If you tell me where that is, I will look. But do I have a sense you may be speaking of a CJ? I saw a picture of a CJ block on Ebay and I seem to recall it had some ribs that looked odd to me. I am seeking out info on my options, and if replacing the block is one of them, I will need to research that. Somehow I do not think I have ribs! By the way, IF I did find a CJ block, would I be able to use all my other junk, such as the crank (IF it is IU) and heads, manifold etc... ? A person told me that a c6Me was a block that was used only as a "replacement" product. That Ford would make good on a warranty, for example, and use one of those.

Are we talking about the Concours d' Elegance here or a nice driver? Why is it so important to get the CJ block if what you have runs fine (after replacing the head gasket)? I say this because when you are dealing with 1966 parts it is not the same as something less than five years old. In a newer situation you can get guaranteed replacement parts and be sure of a reasonable selection of whatever parts you need. When you are talking about finding a CJ block on E-bay that is a pure crap shoot where you might get what you want or maybe you will get another "slightly different" part. I have bought old blocks in a naive assumption that it was what I thought it was only to find cracks and other discrepancies upon closer examination. The point is that the older the part, the less likely you are going to find a true New Old Stock (NOS) part and if you do you can be sure the price will be high, while just because the price is high that may not mean the part is what you think it is. If this 410 runs OK after replacing the head gasket I would run what you have unless you are planning on the Concours d' Elegance; maybe you were since you wanted matching VIN numbers? My best guess is that you have a replacement engine and that is good considering the age of the car unless the odometer says something very low. If the Odometer is over 80K miles and you have a replacement engine I would consider that good and enjoy the car. Perhaps some previous owner thought that replacing the engine with a FOMOCO authorized replacement was a good idea and who knows whether the original block threw a rod and was perhaps un-repairable anyway. Otherwise take it to a high priced restoration shop that has a good reputation and take your pocketbook with you. I certainly leave it to DennyW and Tech1 for personal experience on big-block Ford engines, but personally as a poor boy most of my life, I would paint it, put new tires on and drive it on Sunday; just my opinion.

Don Shillady
Retired Scientist/teen rodder

I was not at all into engines, though my father was a rocket engineer and I married a motorhead biker and after all this time I thought- if you cannot beat them, join them. So I did- IN FULL force, and now I have made a terrible mistake in the car I am afraid![/QUOTE]

:) Hey ................ mmmmmmmmmm, not sure how to approach this one. But here goes. You bought the car so you could have FUN right, so no need to think you made a mistake, think of it as a challenge, you obviously took a big leap into this and are asking for advice,fair enough, thats what we are here for. "Me", I admit Idont know a whole lot about Fords, I am a Chevy man myself, but there are plenty of Ford men here. But one thing I do know with my passion/hobby is how to have fun.

And in hotrods and cars there are many ways to achieve having fun as there are guys and girls twirling wrenches and it is a great learning curve too, with people as well as cars, and, okay I will throw in learning new computer skills as well. I have been with engines ever since I was 3 and I am always learning something new any number of ways. Sure there are some days where things dont go right, but it wouldn't be a challenge then would it ? What else ? oh it will cost money but if you spend it having fun, it's well spent in my view. You only have one life so make the most of it. Well I have said my bit. :rolleyes:

Well the 66 Q code should be a 428. But from the tag and the crank stroke measurement it sure sounds like a 390. It could have been a service replacement even under warranty at the time. It would not be the first time a Ford dealer had installed another displacent engine to substitute a blown or defective part unknown to the customer. OR someone went to a lot of trouble to find a 66 390 to replace it. Either way the car should of had a 428 when it rolled off the line. If it was sold to you as numbers matching it ain't. The ribs you saw on that supposed CJ block were used on every service and production block from 72 and later. So you were looking at a 428 service block not an actual production CJ block. But in some concours circles the service blocks are accepeted as original replacements. The blocks date code is key sometimes. But your Q code bird should have a std 428 not the CJ. If you have to know exactly what you have you'll need to remove one head to measure the blocks cyl bore and either remove the oilpan to ID the crank or get an exact measurement. You can put #1 on TDC, remove #1 and 4 sparkplugs and get your measurement there. You use a lenght of wood dowel or stiff wire and insert into each plug hole and mark. Be sure to use a common edge as a guide...the meausre the distance between the 2 marks. This will be your stroke. The Q code 428's used std parts as far as heads and intake. So those would possibly be the same on either a 390 or Q code 428. But the 66 428 had 345 hp vs the Z code bird 315 hp 390. The C6ME block casting number was generic and used on many different bore blocks from the day. This makes IDing the block difficult. As far as making a 428 out of a 390 it depends on what cyl wall cores were used when the block was cast. If it does have thicker wall cores and coreshift providing you could. But it's a crapshoot till you measure for sure. Most 390's have std 390 wall cores but a few have been found with thicker 428 walls. JMO....G.

Don't be too eager to blame the guy you bought the car from for ripping you off, he may have believed it had a 428 in it. Many Ford garages resorted to stuffing in a 390 (or 410) when a customer had a record of blowing up 428's. You'd be surprised how many 428's......aren't.
As for 410's being ID'ed as 390's, many pickups into the '70's that were sold as 390's had 410's in them. Ford must have overproduced 410's and wanted to get rid of them.

The 428 has a added weight on the harmonic balancer also (external balance)

Ron:HMMM:

I tend to agree with some of the comments about "does it really matter?" So it isn't (maybe) a 428, big deal. Why are you so hung up on those extra 38 cubes? If you figure it diminishes the value of the car, I am not a purist, so that is only something you can know. But as far as the car being usable and just as much fun with the 390, I can't see where there is any difference.

Not to insult your car, but it is a '66 T bird, not something as rare and expensive as a Hemi Cuda or COPO car. It is still a great car, so just have the engine work done, drive it, and enjoy it. If you want it to be a 428, tell onlookers at shows and cruises that's what it is. They won't know the difference, and we all tell little fibs about our cars sometimes.:3dSMILE: :3dSMILE: :cool: :cool: :rolleyes: :rolleyes:


Don

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Originally Posted by shoprat

The 428 has a added weight on the harmonic balancer also (external balance)

Ron:HMMM:

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That's the SCJ only. It used the "cookie cutter" crank spacer to put the missing crank weight pad on the nose to balance the heavier LeMans rods. It also used a larger dia and thicker harmonic balancer from the 427. If you put a CJ and SCJ crank side by side you'll see the CJ unit has a extra weight on the cranks 7th counterweight. The SCJ does not. Also the CJ and SCJ flywheels have different weight pads but as mentioned both and the std 428 are all external balance. The CJ and std 428's used a FE stock balancer with another exception. The 428 PI's I believe used the larger dia 427/SCJ harmonic balancers. But it's been a few years and the mind ain't what it used to be. LOL. I'm pretty sure my old 67 Shel had one tho...:HMMM:

I'll agree with everyones train of thought....if the 390 is a good running engine enjoy it and leave well enough alone. The 66 bird is a wonderful ride so enjoy. If a 428 is what you must have you can shop and build a shortblock and change it in the future. It's next to impossible as mentioned to tell a 428 from a 390 from the outside anyway. But that is your decision. :)

G.

and shed light on the mind of an amateur. The GENERAL principal I am going by is that if the car was built a Q code, I would like it to in fact measure up to that. Since civilization does not forward itself on slipshod satisfactions, I will troop ahead with the goal of consistancy in the car. Had I purchased the car with a Z code and it ended up with a 428, I would have addressed that equally. So for me, it has absolutely nothing to do with appearances. Most cars have a hood that closes. I take the state of my interior life as seriously as I do the exterior- there is nothing worse than a hog in earrings, and the car should be truthful, so to speak. No it is not a show car, that is certain. And I am not a Super Model, but I am obliged not only to look my best, but to BE my best. And that is akin to the well-known correlation between people (most especially men) and their cars. Seldom is found a car that appears perfectly on the outside and open the hood and it is a tangled mess.

Okay, the weekend effort will be to produce a piston, and a reading of the flexplate contents and crankshaft ID. Once I have that, I will be thrilled to hear your comments if by than you have not wearied of the discussion. I see so much generosity and patience with you more experienced enthusiasts and that is just so nice!

Since I have an aircleaner with an old 428 decal on it, I am fully prepared to scrape it off if needed. I know that is important to have fun, but that can wait.

Another great site that can help answer all your questions is www.fordfe.com. Its full of some great people that are knowledgable and patient.:3dSMILE:

I will be thrilled to hear your comments if by than you have not wearied of the discussion. I see so much generosity and patience with you more experienced enthusiasts and that is just so nice!


I can only comment from my own perspective, and would not ever attempt to tell another car enthusiast how he or she should approach the hobby. That being said, I think you are making a mountain out of a molehill on this subject. While I understand that you paid for one thing and possibly got another, that is no reason to have this be the monumental issue it has become for you.

But then again, I have never really understood the hardcore restorers who are so hung up on whether a car has the exact number of threads showing on the ball joints and if the correct length cotter pin was used on the draglink. I have too much regiment in my daily work life, so cars are my escape from that and I take them for what they are........fun, and a toy.

The other thing, as I mentioned in my earlier post, is that you are talking about a 1966 T Bird here, not a historically significant aluminum frontend muscle car. Please understand that is not being said to in any way knock the car, but it is what it is. The car is just as valuable with the 390 probably as with the 428, or pretty close. Why beat yourself up over something as insignificant as this minor difference? It is probably a great automobile, so fix the heads and enjoy it for what it is.

You sound like a person who is very precise in every aspect of your life, and who is driven toward perfection. I was an "A" personality too, until I had my first heart attack at 43. Then I realized that life is a little easier on you if you roll with the punches and compromise a little. Loosen up and enjoy the car, otherwise you are going to drive yourself nuts over those lost 38 cubic inches.

I hope this post comes across the way it was intended. I just think as a newcomer to this hobby you should learn to have fun with it and not make it something that has to be so D*** perfect in every respect. Cars are cars.


Don

well said Itoldyouso

Okay, I am back- the 428 was a 390 after all. This was clear from the crank and the absence of that weight thingy on the ring gear. I want to replace it with a 428 engine so I will be working on that, but I would have a question about my heads, which are in the shop. They are 390 of course, do they fit a 428? And the intake manifold is c6ae9425-g. I resist boring out the 390 for some reason, but I won't say why because that will irritate Itoldyouso.

First of all, I apologize if my post came across the wrong way. Maybe I was a little short with you, and that was wrong. I'm sorry for that. Sometimes when we go back over something we wrote we find we would do it differently if given the chance. It was rude of me to do it the way I did.

The only reason I posted what I did was that I was trying to say I felt you were getting hung up on something that is very insignificant in the overall scheme of things, and that you should just relax and enjoy the car for what it is and the pleasure you are getting from it. However, in reflecting on the situation, I guess this 428 thing is important to you, so who am I to say that is wrong.

The car will not be noticably different performance wise with the 428 vs the 390, but in rereading the thread, that doesn't seem to be your goal anyway. You bought it as a 428 and that is what you want it to be. That is understandable.

One of the Ford experts on here will be able to tell you about the head swap, I'm sure. Hope this clears up any hard feelings between us.

Don

Itolduso Don, I really did not take offense, but let us face it, it is obvious by now I lean towards luxury muscle. I found my husbands 1969 z-28 to be awful, with its roll up windows and lack of air conditioning. So you see? For some, that car is just the greatest thing and I can't bear it! Thank you for your comments, really. I know TBirds are not at all fashionable, but I think the only reason my husband would help me it all is IF it had been 428, that interested him a bit. I told him that in exchange for a Jims 120 could he help me with the car and he said he would, and now I have little to offer! He is guiding me along anyway of course and gave me a pan of gas and the manifold to clean - so I march along, though I absolutely hate the gas and the pan and am wondering why has not some woman invented lemon fresh gas or at least spring scented. The gas melted off my Playtex Living Gloves, and thank God I do not wear fake nails! I am going to look for a 428 to put in there, so any one who could give input on that?