Hello all,

I have a Dart with a 440. I am installing a new transmission. I think the previous owner had a converter and flex plate for a cast crank 440. All of my new components are for a internal balanced steel crankshaft motor. I want to make sure the crankshaft is steel.
Can you tell from the rear flange. I am pretty sure this is a 1973 motor.
Maltese cross on engine identification pad.

Does it have the dampner for the cast crank? Did it vibrate badly before? What I'm getting at is if it was smooth before then you need the properly balanced converter that you took off

Gus

Here’s a photo of the balancer.
I am finding all sorts of things that are spooking me as I go through the car.
I just want a second set of eyes to verify. Everything says steel crank.

Did your converter or flexplate have weights on it? That looks like a forged crank dampner though also the crank not being drilled for a manual input also says later model forged or cast crank. Most of the 440 forged cranks I have used were at least rough drilled for a 4-speed pilot.

Gus

It had a vibration that came in at about 3500 RPM. It had the round flex plate with the bite section, and the converter had 3 weights on it.
I was thinking this being a steel crank motor with these parts was the cause of my vibration.

Low mph cruising or heavy acceleration from a stop, no vibration. Interstate cruising around 60 mph vibration comes in.

My thinking is the previous owner assumed it was a late model 440 with a cast crank. Installed late model transmission, flex plate, and converter. My research before I started tranny swap, motor is a steel crank truck 440. I purchased TCI 727, with 2800 stall converter.

There's your problem, if the convertor has weights on it it shouldn't have the flex plate with the "Bite" out of it, it should have one or the other, not both. If it's a forged crank there should be no large weights on the convertor and a completely round flex plate.

Thanks! That was good information.
So, with the vibration I described, could it just have been the converter?
Based on the photo information, do you think I have a forged crank 440?

The harmonic balancer looks like a forged crank balancer but with the crank not drilled for a four speed it could be a cast crank. Only way to be sure is drop the oil pan and look at the crankshaft, that's what I'd do. That way there's no more guessing.

Okay, more work . The balancers should not be interchangeable if there is a concern. I will drain the oil and use a camera.

If you find it's a forged crank that flex plate and weighted convertor would definitely cause an imbalance. And if you find it's a cast crank only use either the weighted convertor or the "bite" flex plate, not both.

Thank you!

Look for the forging or casting number on the crankshaft and post that on here

Remove that after market flex plate and use a stock Mopar flexplate with a standard converter with no weights welded onto it

is there a partial VIN stamped on it? (mid-passenger side near the oil pan rail)

Not so fast,

Converters have two types of weights on them. One set, usually on the side, balance the converter to neutral. If the converter is then to be used in an external balance engine then additional weights, usually on the front, are added for the imbalance. A pic would clarify this.

So just having three weights on it doesn't mean it's an external balance converter.

All that said, nothing external with confirm or deny it's a cast or forged crank. You will need to pull the pan. Look at the parting line on the crank, thin line cast crank, wide line forged crank.

Drain the oil. Use a $20 cell phone bore scope camera to look up at the crank parting line. Stick it thru the drain plug hole.
Doug

I’ve bought lots of motors over the years and I’m not sure I have ever seen a steel crank with no hole at all. The steel shafts I have in my possession all have some kind of a hole, even if it is too small. I’ve even got some steel shafts out of trucks with pilot bushing installed but they had an auto from the factory. I have seen lots of cast cranks with no holes. That being said, never say never with Ma Mopar. If you have a round aftermarket flex plate with the round notch for the imbalance, you don’t need a converter with the imbalance as well. The three weights are probably just for the initial balance of the converter. I’ve got a picture on my phone of the big oem weight for a cast crank 440 I’ll post. I thinks it’s like 13 oz. My bud just bought a 69 charger 4 speed car. They had installed a cast crank motor with external balance and a neutral flywheel. It vibrated starting at 2000 rpm. There is no way to be sure in this situation until you look at the crank. Do you have a windage tray installed? It may be hard to see without pulling the pan. Someone could have taken a cast crank and had it internally balanced. Look for non factory holes or heavy metal in the crank throws. Honestly, you are just guessing unless you pull the pan. My best guess is that you have a externally balanced cast crank, a flex plate with the proper external balance already on and a neural converter. All this would match. If that is the case,the neutral balancer on the front needs to be changed to an external one to balance everything.

That’s the plan

Did it shake in neutral just revving the engine up?