I have a 312 block that I want to rebuild for a 56 tbird. I am not really concern about having the proper casting numbers. But the casting number for the block is ECZ6015-B. I have a choice of two different sets of heads, ECZ-G or ECZ-C. What is the difference in the performance of these heads and will one "work" better with this block in this car?The car is a automatic. Am looking to rebuild with stock parts not performance.
Which Head to use????
- Thread starter cjc56
- Start date
Hot Rod Reverend
Well-known member
The "C" heads will be the OEM numbers for a "numbers matching" motor. However the "G" heads, which Ford put out in 1957, went on everything from 272's to 292's to 312's. If you are doing a stock build, go with the "C" heads and sell the "G" heads. The "G" heads are worth more money and you will get some takers on their purchase.
Performance wise on a STOCK motor you are not going to see a whole lot of difference between the heads unless you are always having your foot in the car. If you plan to do that then install the "G" heads.
Performance wise on a STOCK motor you are not going to see a whole lot of difference between the heads unless you are always having your foot in the car. If you plan to do that then install the "G" heads.
Thanks for the response. I think I will go with the c heads because the G heads are already on a complete engine that I have sitting in the garage. That way I can probably sell the engine together and get a little more. But I need to have the C heads checked to be sure they are rebuildable. Hot Rod Reverend, I notice that you are in Va, I live just outside Richmond and am having trouble finding anyone who wants to rebuild this 312. Do you have any recommendations?
Hot Rod Reverend
Well-known member
I know what you mean when it comes to difficulty with Machine shops. I actually travel all the way down to the Suffolk area to a shop called "Felt's Machine" - they do excellent work and know Y blocks pretty well. It is a family run operation but do not be fooled. The owner's first car was Y block powered and he messed around with them quite a bit in the day.
Two other Y block fellas in that area use them extensively and have always been very happy.
when you call ask for Travis
I am sure that Suffolk is a whole lot closer for you!
Two other Y block fellas in that area use them extensively and have always been very happy.
when you call ask for Travis
I am sure that Suffolk is a whole lot closer for you!
sidevalve8ba
Well-known member
If I remember my Y-block history properly the G head was the best factory built head for the Y-block from a performance standpoint. It seems to me they were only available in 1957 and had larger valves and ports than other Y-block heads. I am sure someone will be kind enough to correct on this if I am wrong.
dmsfrr
Well-known member
The smaller chamber bigger valve 'G' heads can give you better performance on a 312, especially if you have a '57 style 4bbl carb/intake/dist and '57 exhaust manifolds. If you find a set of stock hi-ratio 1.5 rocker arms that's icing on the cake, and all with OEM parts.
If you're not looking to make that many changes the 'C' heads should be fine.
http://www.ford-y-block.com/cylinderheadchart.htm
However you plan on driving the car and whichever heads you use, you'll probably want the hardened valve seats for running unleaded fuel. Save up your lunch money for the machine shop bill.
FYI. The drivers side exhaust manif. is an ECJ-9431 T-Bird only part.
The 55, 56, 57 T-Birds originally used 'that-year-only' distributors. The carburetors / vacuum ports & distributor advance mechanisms are different for each year.
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dmsfrr
Well-known member
Since you're wanting to stay with the rest of the stock 56 top end parts I think any performance difference between the C or G heads would be minimal.
I agree with the previous comment by Hot Rod Reverend.
If the extra air/fuel can't get into or out of the G head it won't do any good.
You said the G heads are on a complete engine you're considering selling. What is that engine? They do make it worth more.
I agree with the previous comment by Hot Rod Reverend.
Because, to get 'better' performance out of the G heads you'd need to have virtually all of the complete higher performance stock '57 setup: carb, cam, ignition & intake/exhaust manifolds to take advantage of the extra flow potential in the heads.
If the extra air/fuel can't get into or out of the G head it won't do any good.
You said the G heads are on a complete engine you're considering selling. What is that engine? They do make it worth more.
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Fortunateson
Well-known member
This is a great thread. I have a '56 Rideau Victoria with a 292 and was wondering about swapping to the "G" heads before I finish the rebuild. What kind of HP/fuel consumption changes would I notice over the "C" heads if. I do switch?
dmsfrr
Well-known member
You'll probably get a bit less mpg, mostly cuz your right foot will get heavier, and have more hp with a good complete engine setup.
Someone else may give you some real-world numbers but not me. Because my '55 T-Bird had a messed up non-original engine when I got it, and it's not back together yet.
Even if it was running I don't own it for it's gas mileage.
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Fortunateson
Well-known member
I don't own any of my Vintage vehicles for their fuel economy either! Too much fun. I was just trying to see if it was really worth making the change. If it would be really obvious then I would otherwise I don't think it would be worth it.
dmsfrr
Well-known member
Making a change is pretty much up to you & your budget, and how much you think the parts & time are worth to you for the difference. At the best you might get an extra 25/30ish HP and lose 2/3 mpg if you upgrade the whole intake, ignition & exhaust setup.
I'm getting lazier after all these years and not as inclined to change something 'just cuz it's possible'.
If I'd had a complete original engine to start with I probably wouldn't have changed much at all. But since I had to start from scratch with a replacement block & heads I picked the various parts I wanted that were available and close enough to my budget.
Enjoy!
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Fortunateson
Well-known member
Has anyone heard of anECZ-B head? I have a got a set and the fellow said they are Canadian
dmsfrr
Well-known member
An ECZ-B head is a '56 4bbl 292 & 312 head. Probably used in the early part of the model year on T-Birds & Mercury's before they changed to ECZ-C heads. I believe the C heads have a slightly smaller combustion chamber, with a bit higher compression ratio.
See this link...
http://www.ford-y-block.com/cylinderheadchart.htm
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scicala
Well-known member
There were no heads that were used on Canadian only vehicles that I'm aware of. Makes no sense also. ECZ - B heads were used in 1956 on the original 312 (215 HP)that was introduced that year. They had a slightly larger combustion chamber than the ECZ - C heads (312/225 HP) that came out a little later in the 1956 model year, so ECZ - B's had a lower compression ratio. As far as I know they were used in 1956 production only.
Fortunateson
Well-known member
Thank you guys. When I got my '56 Meteor Rideau Victoria many years ago the engine was apart. I was trying to determine if the fella I got it from had done any upgrading. It appears to be no. But I won't be out to race the car just to drive at moderate speeds for all to admire!