Small block engine mount question

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Señor Ding Dong

Señor Ding Dong

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Hey all, I have a tired old 1971 la318 in my 66 Dart, and I’m swapping it for a much fresher 1974 la318. I’m just about ready to do the swap, but the mounts look slightly different on each. Am I crazy, or is that normal? The 74 came out of a 69 Dart, and the mounts appear to sit much closer to the block than the one currently in my 66.

I couldn’t get clear pictures of the 66, it was too dark, but if needed I can try tomorrow.

If this is all normal and fine, can I just swap engine mounts from one block to another?

Thanks!
 
The blocks are the same. 74 would have had spool mounts and 71 would have had biscuit mounts. If in doubt, pull the mounts off your old block and put on your “new” block. Make sure the mounts are on the correct sides of the block “ears”
 
The mounts and brackets are the only thing that's different. Just swap 'em over.
 
67 through 73? (What ever year was the last to use the biscuit) SB do sit close to the block.

66 and older are different as the k frame is different.

There is also a possibility that you have a /6 k frame in your 66 and the mounts are swap mounts.

As stated above swap the metal mounts and rubber isolators (biscuits) that were in your 66 now on to the new motor.

Assuming the old motor in the 66 fit correctly.


BTW...

I don't know if this will effect you but it was pointed out that later smog motors have a extra pad under each exhaust port for air injection and 66 and older stock exhaust manifolds hit it preventing the manifold from seating.

1965 MOPAR, 273 Exhaust Maifolds.
 
Last edited:
Dana67Dart said:
67 through 73? (What ever year was the last to use the biscuit) SB do sit close to the block.

66 and older are different as the k frame is different.

There is also a possibility that you have a /6 k frame in your 66 and the mounts are swap mounts.

As stated above swap the metal mounts and rubber isolators (biscuits) that were in your 66 now on to the new motor.

Assuming the old motor in the 66 fit correctly.


BTW...

I don't know if this will effect you but it was pointed out that later smog motors have a extra pad under each exhaust port for air injection and 66 and older stock exhaust manifolds hit it preventing the manifold from seating.

1965 MOPAR, 273 Exhaust Maifolds.
Click to expand...
I wasn’t aware you could mount a v8 on a /6 k member, I just assumed it had been swapped. I’m guessing you’re right though. Any detriment to that?

And thanks for the heads up about the manifold. I’m not at home, but in pics on my phone it doesn’t appear the heads have air injection ports, so I should be good. I’ll test fit the manifolds before I drop the engine in, just to be sure!
 
Señor Ding Dong said:
I wasn’t aware you could mount a v8 on a /6 k member, I just assumed it had been swapped. I’m guessing you’re right though. Any detriment to that
Click to expand...
The aftermarket makes /6 k member to small and big block.


These are 67 up and there might be fewer offerings for 66 and down but they do exist.
Screenshot_20240229-131106.png


Screenshot_20240229-131031.png


V8 conversion mounts.
 
Señor Ding Dong said:
And thanks for the heads up about the manifold. I’m not at home, but in pics on my phone it doesn’t appear the heads have air injection ports, so I should be good. I’ll test fit the manifolds before I drop the engine in, just to be sure
Click to expand...
I have a 79 318 and it has the ports. But I got lucky that the 67 up 273 manifolds fit proper.

In the post it mentions that you can not grind the riser on the head as the water jackets are too close
 
Dana67Dart said:
I have a 79 318 and it has the ports. But I got lucky that the 67 up 273 manifolds fit proper.

In the post it mentions that you can not grind the riser on the head as the water jackets are too close
Click to expand...
I haven't run across problems with the '67-up manifolds. It's the '64-6 LH exhaust manifold that can have an interference problem at the #7 exhaust port on a smog head. Some castings are worse than others, but, some can be ground to gain the clearance you need. It's easier to just space the manifold out a bit rather than take the chance of grinding into a water jacket.
 
In case all the different answers that say kind of the same thing have you still wondering....unbolt the mounts from your existing engine in your 66 Dart and bolt them to the replacement engine. Just do them one at a time so you don't accidentally swap them side to side. It's just 3 bolts per side, and super easy.

:thumbsup:
 
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