Thread: Did I buy a 428 and get a 390 Thunderbird?

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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.

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.