Hey, they made a completely new head (peanut head) and the only major difference was the lack of drool tubes. No bigger valves, no improved ports or combustion chamber. Why-Why-Why???
jus sayin

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-MattMan
LEANED & MEAN

What year did they go to cast cranks?

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I am not really certain, but I have heard they started around 1976 ish. My 79 engine is a cast crank motor and the 73 is a forged crank motor.

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-MattMan
LEANED & MEAN

It was a running change in the 1976 model year. 1976 vehicles could have been built with a forged or cast crank slant, depending on what engine was coming down the assembly line.

So the forged to cast crank is in the same time period as the hold down change...………………...

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

It looks that way, but it could be unrelated. Who knows.

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-MattMan
LEANED & MEAN

I believe the change in hold down was made after the switch to cast crankshafts. Very late 70s or early 80s.

I have an older block and use the newer two-piece hold down. My block seemed to have a surface for the tab to leverage against to hold down the ring, but now that I've read this thread, I'm going to have to check to see if I'm correct. Hmm, maybe I used a different hold down clamp from a V8 or something or it's not holding it down as well as I think...I'll check on both and post a reply on what I find.

brian

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https://tinyurl.com/yynpj4v2

None of the V8 ones (Mopar or otherwise) will work on the slant block without some changes. The Mopar big block comes closest, but even that one needs a lot of work. A slant six claw WILL work on earlier blocks to some degree, just not as well as it would on the blocks it was designed for. I will try to take pics of the claw on early and late blocks.
jus sayin

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-MattMan
LEANED & MEAN

That's great if you can post pics, helpful info for the community.

My dart is at the body shop right now so I can't check. Honestly, the gray cells go over time, i don't recall if I used a slant hold down or some modified thing I made...I'll be able to check next weekend, hope to get my car back this week.

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https://tinyurl.com/yynpj4v2

The newer style hold down does not work with at least some older blocks. I run the newer style hold down on the older block, because of the extra adjustability it gives. I had to cut the piece that is supposed to hit the block and move it closer to the hold down bolt so it would hit the block. I think I also bent the forks a little bit down as well. This ain't rocket science.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I posted what information I could (in two parts). I don't claim to know everything about these, but I did want to share what I have discovered. I personally prefer the claw style mount for its range of adjustability.
Like Rick says, it isn't rocket science.

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-MattMan
LEANED & MEAN

I have used the 2 piece one on my forged crank motor without any modifications. Guess I'm just lucky.

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Official Cookie and Mater Tormentor.