Starting engine build, which block do I use?

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SalmonTex

Active member
Joined
Dec 17, 2012
Messages
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Location
Dallas, TX
My Car
1973 Mustang Mach 1
Bright Red
I am starting to build the engine for my restoration, and have two options to consider. I do not have the original block or internals (I think), but according to the VIN the car is a Q code.

OPTION 1:

It's was my dad's car and he had a performance shop build the engine for him when he was 18. He said it was built for high compression but doesn't remember the HP it made. They used the stock 4V heads, added an Edlebrock Scorpion intake, 1050 CFM carb, electric fuel pump. This engine is not in running condition (Even though it has less than 20K miles on it), having zero compression in the #6 cylinder that we believe to be a hole in the piston. Too advanced of timing possibly? We aren't sure what was done internally to the motor (He doesn't remember), but I don't think it's the original block because it is stamped as a DOAE shown in the pic below. I am doing my best to scour the web for stamp code information, but it seems that the information is not always consistent. I am not finding anything that matches this--most sources claim that the code should be DOAE-L,C,J, etc. Does anyone know what it means for this block to not have that secondary letter?

14jvzae.jpg


OPTION 2:

Mileage - unkown. My dad's dad (My grandpa), found a 351C-2v motor at a junk yard and bought it for my dad as a gift, in hopes that he would drop it in the Mustang to get it running again. This engine is supposedly in running condition, but has had no internal work done to it. It is a D2AE-CA block, which I believe to be closer to a "number matching" block.

slk1g9.jpg


2ufetrm.jpg


I'm looking for some input on the two stamping codes, more specifically is one a better block to start with than the other? I am leaning toward the hi-po engine that my dad had built as a kid (OPTION 1) under the assumption that the internals were beefed up so there would be less work I'd need to do. I am looking for something in the 300-350 HP range, nothing crazy. Numbers matching is not essential, but of course would be a bonus. Thanks in advance.

 
Hello,

The DOAE block was used in 4V 1971 Mustangs and so would not be correct for your 73.

The D2AE block was used in 72/73 Q codes and some of the blocks had 2 bolt mains and some had 4 bolt mains. This would be the correct block for your car. The numbers below the block code are the date code but I cant read from pic. If you compare this date to the build date on your car it might be close.

One other thing is a partial VIN was stamped into the blocks on the LH side right below the head. Here is a pic of mine. May be hard to see but should be there. If this matches your car you know its the exact matching numbers one.

9k2p92.jpg


 
Either build will get you 350 hp no worries. If all the parts match to combo for its intended purpose. 1050 carb I think your dad was a bit ambitious there. Good luck with your build

 
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The D2 block is into the 74 date codes. If both blocks have the heads removed, measure the bores. If one is standard bore, I'd be looking at that one to build. You won't know what you have until they are both apart and inspected. Chuck

 
Thanks for the responses guys. I took the supposed high performance D0AE engine out of the car this weekend and took it to an engine shop. Hoping to hear this week on what they find and go from there. Here's some more pics:

6e27b5.jpg


2dkcphx.jpg


14nlehe.jpg


 
Update on the engine build. The engine shop contacted me and there is good news and bad news. Good news is that I have closed chamber 4V heads. Bad news is that one is cracked. Now I have to decide if I want to track down another 4V closed chamber head or swap in the 2V open chambers I have in the garage. Probably a wash in cost after I replace the intake manifold along w/ the switch to 2V heads. I'm leaning toward keeping the 4V's but I'm interested in hearing feedback.

 
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Hands down. Go with the 4v CC. Find another but make sure it matches. There might be slight differences that other can point out. One example is both adjustable and non-adjustable rocker pedestals were used.

 
I would stick with the 4V CC. Where is the crack? Chuck
I'm not quite sure. What's your reason for asking? I will get more information the next time I talk to the engine shop, but my guess would be somewhere near cylinder #6. When doing a compression test before pulling the engine, we were getting ZERO compression on #6, and about 75% compression on the two adjacent cylinders.

 
So where's the best place to find a CC 4V head? I see a few on eBay, but seems like it would be hard to trust someone on a part like that as far as cracks, condition, etc.

 
I have a pair of stripped castings, 4v Open Chamber heads. No cracks, no bad threads, no damage-I pulled them off while the engine was running perfectly. If you want to go that route, I'll make you a good deal.

With the proper pistons, Open Chamber heads perform quite well.

 
The engine shop has a source for some 4V CC heads and the guy wants $450 for the set and is throwing in a matching stock intake manifold (Though I probably won't use it). He is also suggesting this cam: 214/224 @ .050 duration and .510/.536 lift, hydraulic lifters. The car is an auto w/ C6 trans and I will be keeping stock wheels/tires for at least a few years. Any feedback is appreciated.

 
If the valves in those heads are the stock multi-groove style, they are worthless and should be discarded.

SalmonTex, before you proceed any further... what are you prepared to spend on this engine rebuild?

 
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As MotoArts said, you are buying the heads as cores. You won't re-use anything other than the heads. As far as the cam is concerned, what are your goals for the car? What gear, what convertor, etc.. Chuck

 
As MotoArts said, you are buying the heads as cores. You won't re-use anything other than the heads. As far as the cam is concerned, what are your goals for the car? What gear, what convertor, etc.. Chuck
Not sure about the gears. I know it has the stock C6 trans and will be having a friend rebuild that next, so my options are open. I'm still catching up on my research of the engine, haven't made it to the trans yet. Until now I wasn't planning to modify the trans from stock, but I'm guessing if increasing power, it only makes sense to adjust the gearing accordingly.

Motoarts, i want to build it right as I plan to drive the car regularly and keep it long term, so I'm prepared to pay for quality parts and labor. I have considered a crate engine, but I would much prefer to keep this a Cleveland-powered car. Based on initial estimates from the engine shop, I'm looking at $2.5-3k all in not including the 4v cores.

 
Here's the deal with the heads... and I guess the rest of the build as far as it's concerned... strictly in my opinion.

There are many, many options available when building engines.

And opinions far outweigh these options...

My opinion is that those CC heads are priced a bit stiff, especially if they are stock and untouched. I normally see good cores selling in the 250-300 range.

Your quote from the builder seems to be on par with what should be expected, so that's good.

I do almost all of my own work, so keep that in mind.

I have read many times that people (can) get nearly as deep in a set of stock heads than a set of modern, ready to use alloy heads as far as cost is concerned. Yes, even though I provide my own labor, I can believe the figures that I see.

Cleveland parts often times are more expensive than the sea of Windsor stuff floating around, so don't get confused, surprised or discouraged.

Do be careful, educate yourself, and weigh your need-versus-want baskets often :) For a street engine, I feel that there are a lot of machining steps and extensive parts lists that are "suggested or recommended", and not really "needed".

Have fun with it, we'll be watching your progress!

 
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The cam sounds like it is a Lunati cam. Assuming it is ground on a 112 Lobe Separation Angle, it should work fine for a mild build with a 3.50:1 gear and stock 351 CJ convertor. Do some reading on Static vs Dynamic Compression Ratio and oiling modifications before you finalize parts selection. Good luck on the build. Chuck

 
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