429 Help Please. It's A stumper

[NightHawk]

I've picked up a 429(?) engine for free. I'm wanting to rebuild the engine and the first thing I come across already stumped me and everyone I've called and anywhere I've looked online. The emissions decal is faded but I see enough on it to give me a little information about this engine. I see where the ignition timing is set at 4 degrees off center and idle setting at 590RPM for a automatic transmission. Their is no setting for a manual transmission. That's part of what's stumping people. But the biggest hang up is the D0AE-9C485-T. We all can find anything we want for that serial number under ever letter and letter combination in the alphabet except the letter T. I know the D0AE-9C485-S is a 351 and the D0AE-9C485-U is a 429. Does anyone know what the D0AE-9C485-T is? I've called many places and looked up many places online but to only stump everyone what the T series is. Thank you for any help.

[jerry clayton]

Its a part number , not a serial number----

[rspears]

NightHawk,
Welcome to CHR! From your post it's pretty clear that you understand very well how to read the part number segments (even though you called it a "serial number by mistake), as spelled out in the post above. Unfortunately, the meaning of that "T" ending character is illusive!

Hopefully one of the guys here will have something from some old 1970 info that spells it out for you. Glad to have you here.

[NTFDAY]

You might want to check out this site, I didn't feel like becoming a member.
Read 1969 - 1970 Boss 429 Mustang Unique Parts List

[NightHawk]

Yeah sorry guys I did write serial (just retired army so still a habit lol) I did mean part number. It belongs on the exhaust emission control. But yeah that T is a pain trying to figure out. Just trying to make sure I understand what this engine is before I start rebuilding it. Because this is my first ever ford project because it was given to me free. Thanks for the correction.

[HOSS429]

you only need to tell your parts guy you have a base 1970 429 ....not a cobra jet.. not a boss .. is it a 2 or 4 barrel engine ? .. even that wont make a diff in the rebuild kit ...

[NightHawk]

you only need to tell your parts guy you have a base 1970 429 ....not a cobra jet.. not a boss .. is it a 2 or 4 barrel engine ? .. even that wont make a diff in the rebuild kit ...

Yeah I knew it wasn't a boss or cobra jet. People would be having a hard time if it was one of those engines. But you did answer the question about whether it's 2B or 4B. Because I wasn't sure if the parts were different. But if it's all the same then that makes life easier.

[techinspector1]

Anything before about 1972 would be a high-compression motor with non-hardened exhaust valve seats and small (~76 cc combustion chambers), although it would be fitted with the correct camshaft timing chain sprockets for hot rodders. The later timing chains (73-up) featured retarded cam timing (by about 8 degrees) in an attempt to lower emissions so the motor would pass Federal standards. The hot tip for these later low compression motors is to change out the timing chain and sprockets for a '68-'70 429 part number, so you have the proper timing chain and sprockets to begin with.

Your motor has probably around 10.17:1 static compression ratio and iron heads, so running it on pump gas probably won't work due to detonation. Back when this motor was new, we had Sunoco 260 fuel (110 octane) available on every other corner, so fuel was not the problem that it is today. Also, the fuel had tetraethyl lead in it to lubricate the exhaust valve seats so that the valves would not wear down into the heads. Actually, it didn't lubricate the seats, it made them dirty. Anyone who knows anything about welding knows that you have to have a clean connection in order for welding to work properly. What happened was that when the exhaust valve was seated on the seat, a little micro-welding would take place. When the valve was lifted off the seat, it would tear itself loose and take a little material from the seat and deposit it on the valve face. After a while, the exhaust valve would wear the seat away so much that the valve itself would be recessed down into the head. Engineers found that if they put a little tetraethyl lead into the fuel, it would dirty-up the seats and no welding could take place. We used tetraethyl lead for many, many years until it was discovered that we were destroying the planet with lead. That's why we have unleaded gas today and why we have a problem once again, with the valve recessing down into the head. To fix this, we have begun to add hardened exhaust valve seats into the heads so that recession is checked once again.

So, you have to address the valve seats as your first problem.

The second problem is the static compression ratio. Again, when this motor was new, the fuel that was available would prevent detonation on motors up into the 11.0:1 and 12.0:1 static compression ratios. Today, with iron heads, smart money limits the SCR to around 9.5:1 or just a little higher for using pump gas.
There are a couple of ways you can lower the static compression ratio of your motor. One is by changing heads to the later D3VE cylinder heads, which are ~95 cc's instead of the earlier C8VE 76 cc heads, or the one-year only E6TE heads from 1986. That would lower the SCR to about 8.65:1 SCR, which might be a little low for a performance motor, even a street performance motor.

If I were doing one of these motors, I would find a 460 crank and build a 460 instead of a 429. Check with local automotive machine shops for cranks that customers left and on craigslist. You shouldn't have any trouble finding a 460 crank. I'd bore the block 0.030" and use new Keith Black KB137-030 pistons. I'd zero deck the block and use Fel-Pro 17068 head gaskets to arrive at a 0.039" squish/quench. The best power will come from using a dual-plane, high-rise intake manifold such as a Weiand Stealth #8012, mounting a 750 carb of your choice.

This would make a 466 cubic inch motor with a 9.91:1 static compression ratio. You would have to run premium fuel with it, but the zero deck and tight 0.039" squish will help to keep detonation under control. I would use a cam with 214-222 degrees intake duration, cut on a 112 degree LSA. The higher the intake duration, the more the motor will need a looser stall converter if using an auto trans.

.

[firebird77clone]

Thanks for the lead explanation.
Isn't it amazing that the engineers chose to pollute the planet rather than harden the valve seats?

[NightHawk]

Anything before about 1972 would be a high-compression motor with non-hardened exhaust valve seats and small (~76 cc combustion chambers), although it would be fitted with the correct camshaft timing chain sprockets for hot rodders. The later timing chains (73-up) featured retarded cam timing (by about 8 degrees) in an attempt to lower emissions so the motor would pass Federal standards. The hot tip for these later low compression motors is to change out the timing chain and sprockets for a '68-'70 429 part number, so you have the proper timing chain and sprockets to begin with.

Your motor has probably around 10.17:1 static compression ratio and iron heads, so running it on pump gas probably won't work due to detonation. Back when this motor was new, we had Sunoco 260 fuel (110 octane) available on every other corner, so fuel was not the problem that it is today. Also, the fuel had tetraethyl lead in it to lubricate the exhaust valve seats so that the valves would not wear down into the heads. Actually, it didn't lubricate the seats, it made them dirty. Anyone who knows anything about welding knows that you have to have a clean connection in order for welding to work properly. What happened was that when the exhaust valve was seated on the seat, a little micro-welding would take place. When the valve was lifted off the seat, it would tear itself loose and take a little material from the seat and deposit it on the valve face. After a while, the exhaust valve would wear the seat away so much that the valve itself would be recessed down into the head. Engineers found that if they put a little tetraethyl lead into the fuel, it would dirty-up the seats and no welding could take place. We used tetraethyl lead for many, many years until it was discovered that we were destroying the planet with lead. That's why we have unleaded gas today and why we have a problem once again, with the valve recessing down into the head. To fix this, we have begun to add hardened exhaust valve seats into the heads so that recession is checked once again.

So, you have to address the valve seats as your first problem.

The second problem is the static compression ratio. Again, when this motor was new, the fuel that was available would prevent detonation on motors up into the 11.0:1 and 12.0:1 static compression ratios. Today, with iron heads, smart money limits the SCR to around 9.5:1 or just a little higher for using pump gas.
There are a couple of ways you can lower the static compression ratio of your motor. One is by changing heads to the later D3VE cylinder heads, which are ~95 cc's instead of the earlier C8VE 76 cc heads, or the one-year only E6TE heads from 1986. That would lower the SCR to about 8.65:1 SCR, which might be a little low for a performance motor, even a street performance motor.

If I were doing one of these motors, I would find a 460 crank and build a 460 instead of a 429. Check with local automotive machine shops for cranks that customers left and on craigslist. You shouldn't have any trouble finding a 460 crank. I'd bore the block 0.030" and use new Keith Black KB137-030 pistons. I'd zero deck the block and use Fel-Pro 17068 head gaskets to arrive at a 0.039" squish/quench. The best power will come from using a dual-plane, high-rise intake manifold such as a Weiand Stealth #8012, mounting a 750 carb of your choice.

This would make a 466 cubic inch motor with a 9.91:1 static compression ratio. You would have to run premium fuel with it, but the zero deck and tight 0.039" squish will help to keep detonation under control. I would use a cam with 214-222 degrees intake duration, cut on a 112 degree LSA. The higher the intake duration, the more the motor will need a looser stall converter if using an auto trans.

.

Wow that's some awesome knowledge you've taught me and I'll definitely look into doing what you said you'd do with this engine. But the one question I have is should I replace the iron heads or leave them alone?

[NightHawk]

You would actually need to know the month of that 1970. In 1970, is when they installed hardened seats. That was do to running higher temps for emissions. So, that engine may very well already have hard seats.

So with the hard seats I can leave the iron heads, correct?

[rspears]

So with the hard seats I can leave the iron heads, correct?

If you have hardened seats you can run the iron heads with unleaded fuel, but if you opt for aluminum you can push your static compression ratio about one point higher without needing to boost the octane rating. The aluminum heads will dissipate heat faster, transferring heat of combustion to the coolant more efficiently, and if you're careful selecting the new aluminum heads you'll likely get improved flow, too.

[HOSS429]

. But the one question I have is should I replace the iron heads or leave them alone?

if you are looking for some better than stock performance then at minimum you should mildly port and polish the stock heads you have on the exhaust sides. i would not pay the 2 grand required to get aftermarket 429 heads for the minimal improvements you would get in a near stock build .. i did step up and get some edlebrock heads for my 351 but they are much cheaper and well worth the 1000 bucks ..you already have over 300 horses to begin with .. just bump up the cam a bit .. add an intake and headers and good ignition and let her rip .. what kind of car are you looking at ?

[techinspector1]

The compression can be changed by simply picking the correct cam to run on at 91 octane fuel...With what you have...and getting the distributor advance in order, along with timing, and the curve settings...

Just so we don't confuse some of the members here who are learning, STATIC COMPRESSION RATIO can only be changed by changing the cylinder volume, piston deck height, piston crown design and/or combustion chamber volume.

A fellow can, though, change the CYLINDER PRESSURE (the pressure you see on a gauge when you do a compression test of the motor) by altering the cam timing as Denny suggests. Compression in the cylinder does not begin until the intake valve has closed to seal up the cylinder, so if you alter the intake valve closing point on the cam lobe, to closing earlier or closing later, you can vary the cylinder pressure up or down. This is where most newbies make their mistake with choosing a cam for their motor. They might have a low compression motor, something on the order of ~8.5:1 for instance, but they will, out of ignorance, choose a cam that would work well with an 11.0:1 static compression ratio motor. Their thinking is that the cam is a stand-alone part that will make more horsepower in the motor regardless of the accompanying parts in the motor. Nothing could be farther from the truth. The cam is dependent on ALL the other parts in the motor to work in concert toward a certain goal. The result of using a long cam without support from other parts in the motor is that there is little cylinder pressure made until the motor "gets up on the cam" in the higher rev ranges. They are left with a motor that will pull hard from, for instance, 4500 rpm's and upward, but has little cylinder pressure and little horsepower down lower in the rpm range where they operate the motor every day.

Here is a tutorial that I wrote that explains it pretty well....
http://www.crankshaftcoalition.com/w..._compatibility

.

[rspears]

if you are looking for some better than stock performance then at minimum you should mildly port and polish the stock heads you have on the exhaust sides. i would not pay the 2 grand required to get aftermarket 429 heads for the minimal improvements you would get in a near stock build .. i did step up and get some edlebrock heads for my 351 but they are much cheaper and well worth the 1000 bucks ..you already have over 300 horses to begin with .. just bump up the cam a bit .. add an intake and headers and good ignition and let her rip .. what kind of car are you looking at ?

Some good advice there. Hoss knows the costs, and how to get it done. Along with Tech's advice on the machining you're gonna be right, IMO.