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1971 351C 4V question
#1
Today we imbark on trying to find a replacement engine for my '71 M-code Grandé. We discovered a cracked block not long ago and have spent too much time and energy doing a restoration to scrap the car. There is another thread about "how many are left" and this car is not going to be left behind.
What is the difference between a "short" block, "long" block and "block"? I would like to use the existing parts as the engine was rebuilt some years before I owned the car and, except for the crack, all other components are in excellent shape. As I understand, a "short" block is an engine with all components except the heads. Many readers suggested a crate engine but I want to keep this as original as possible. They only made, according to Marti, 100 '71 M-code Grandes with a toploader. If I go the route of a short block or "bare" block, does it matter what year?
On a different note, there are no less than 8 people involved in getting this car back on the road and I only know 3 of them Wink Everyone else wants to help because the car is a Classic Mustang! They are all offering their time, expertise and tools for free. They want to see the car running again.

mike

[Image: 1_11_11_13_11_50_27.png]
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#2
I think you are making the right decision and it is great that you have you very own pit crew. A block is just that the block itself and usually the main caps, short block is the block, rotating assembly, cam, lifters, and timing set. The last few years I've seen short blocks advertised with no cam and timing set. Long block is short block plus heads and rocker arms. As to the block, it would be nice to find one with an appropriate date code but, it really doesn't matter. It is too bad the original block can not be sleeved. I have a great machinist who used to race Clevelands. If you have a photo I could have him look at it and at least get you a second opinion before you scrap the block. Chuck
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#3
Mike,

Chuck is "right on the money" (as usual) with his response.

I agree that it is nice that you have a lot of "help."

Did you get an opportunity to check the mains on the block? I am curious as to whether the mains are 2-bolt or 4-bolt. As previously stated, a "M-Code" could be either. I would think that could influence your quest for originality as you try to obtain a new block.

BT

Do the RIGHT thing.
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#4
What are your final plans for the car? Are you going to show it? Get it judged? Drive it? Depending on what your plans are you have several options. Here are two extremes (not including swapping something other than a Cleveland)

1. Show quality concours judge. Find a block with a date code that is accurate for the build date of the car. Obviously a 73 block would not have come in a 1971 mustang

2. Daily Driver 'stock looking'. You could actually swap in any block and rotating assembly whether a 2 bolt or 4 bolt.

The most difficult problem you will have if you want to keep your rotating assembly, including pistons, is finding a block that has not been bored out. In the very least, you will want to get a new set of pistions.

One thing you might consider, depending on your budget and goal, is consider a brand new block. There is a gentleman who is getting very close to finishing his quest to reproduce Cleveland blocks.

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
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#5
c9zx;36301 Wrote:I think you are making the right decision and it is great that you have you very own pit crew. A block is just that the block itself and usually the main caps, short block is the block, rotating assembly, cam, lifters, and timing set. The last few years I've seen short blocks advertised with no cam and timing set. Long block is short block plus heads and rocker arms. As to the block, it would be nice to find one with an appropriate date code but, it really doesn't matter. It is too bad the original block can not be sleeved. I have a great machinist who used to race Clevelands. If you have a photo I could have him look at it and at least get you a second opinion before you scrap the block. Chuck

At one point I played with the idea of dropping a 427 in it Dodgy but not for long. The car has the toploader, 9" posi and comp suspension package, sooo... Someone posted a picture of some Aussie blocks. Don has a rebuilt block. There is always the junk yard but you don't know what you are getting. I will get a photo when I can but two other machinists said the crack was in a bad spot for a sleeve.

mike

[Image: 1_11_11_13_11_50_27.png]
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#6
cobra3073;36311 Wrote:Mike,

Chuck is "right on the money" (as usual) with his response.

I agree that it is nice that you have a lot of "help."

Did you get an opportunity to check the mains on the block? I am curious as to whether the mains are 2-bolt or 4-bolt. As previously stated, a "M-Code" could be either. I would think that could influence your quest for originality as you try to obtain a new block.

BT

People hate seeing the Mustang just sitting there. Can you believe it. Two of them own 60's Mustangs that my mechanic works on for a song. I have not seen the car since it was towed and it is safely tucked away in the Santa Cruz mountains. We ( I am using the word as a synecdoche) did find a second cylinder on the other bank that had a piston stamped 040 so that explains how they dealt with the imbalance issue, sort of Confused I will get pictures and numbers soon and post them.

mike

[Image: 1_11_11_13_11_50_27.png]
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#7
will e;36331 Wrote:What are your final plans for the car? Are you going to show it? Get it judged? Drive it? Depending on what your plans are you have several options. Here are two extremes (not including swapping something other than a Cleveland)

1. Show quality concours judge. Find a block with a date code that is accurate for the build date of the car. Obviously a 73 block would not have come in a 1971 mustang

2. Daily Driver 'stock looking'. You could actually swap in any block and rotating assembly whether a 2 bolt or 4 bolt.

The most difficult problem you will have if you want to keep your rotating assembly, including pistons, is finding a block that has not been bored out. In the very least, you will want to get a new set of pistions.

One thing you might consider, depending on your budget and goal, is consider a brand new block. There is a gentleman who is getting very close to finishing his quest to reproduce Cleveland blocks.

Have not decided on what to do as there are many options. I would like the VIN to match the engine and that is about all. We do plan on showing the car but not as a Concours correct restoration. The fact they only made 100 of these means we need to keep it as original as possible.

mike

[Image: 1_11_11_13_11_50_27.png]
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#8
If you are not going for concours correct then focus on finding a good block of any year.

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
  Reply
#9
goodnigh;36350 Wrote:
will e;36331 Wrote:What are your final plans for the car? Are you going to show it? Get it judged? Drive it? Depending on what your plans are you have several options. Here are two extremes (not including swapping something other than a Cleveland)

1. Show quality concours judge. Find a block with a date code that is accurate for the build date of the car. Obviously a 73 block would not have come in a 1971 mustang

2. Daily Driver 'stock looking'. You could actually swap in any block and rotating assembly whether a 2 bolt or 4 bolt.

The most difficult problem you will have if you want to keep your rotating assembly, including pistons, is finding a block that has not been bored out. In the very least, you will want to get a new set of pistions.

One thing you might consider, depending on your budget and goal, is consider a brand new block. There is a gentleman who is getting very close to finishing his quest to reproduce Cleveland blocks.

Have not decided on what to do as there are many options. I would like the VIN to match the engine and that is about all. We do plan on showing the car but not as a Concours correct restoration. The fact they only made 100 of these means we need to keep it as original as possible.

mike

Mike,

I reviewed your "Marti Report" again and I am 99.99% sure that based on your engine build date of march 1971 that your Mustang came from the factory with the 4V 2-bolt main block as supposedly all 4V built through 1971 had the 2-bolt mains.

That having been said, and keeping in mind that your 1 of 100 distinction has to do with the engine and transmission (1971 351C 4V with toploader transmission), I do not believe you should have a problem finding a 2-bolt main block. There were actually 419 Coupes built in 1971, so your 100 number is probably the number of Grandé Mustang built - - a rare Mustang to be sure.

I actually have a 2-bolt main block with a date code of 2E23 (1972-May-23) which tells me that the 2-bolt main 351C blocks were built at least through May of 1972.

Hope this helps.

BT


Do the RIGHT thing.
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#10
goodnigh;36350 Wrote:Have not decided on what to do as there are many options. I would like the VIN to match the engine and that is about all. We do plan on showing the car but not as a Concours correct restoration. The fact they only made 100 of these means we need to keep it as original as possible.

mike

If you get a different block, the VIN won't match. You may match the casting and date, but not the VIN. I have seen blocks welded and sleeved, but the machinist needs to really know what he's doing, and it depends on where the break is. At .040 overbore, you would have been looking at a new block or total resleeve in the future anyway. I'd just buy another block and save the old one in a corner until you find someone that can fix it correctly and you feel like putting the money in to it that it will need.

Steve
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