hello, did the 400 ever come with a Forged steel crankshaft from the factory? I had always been under the impression that they were all cast( at least the dozen or so I have disassembled) but saw in some book today that showed a parts listing claiming a steel crank.so, did they? and another question, I need a external balance damper for a 383 cast crank, I have a external damper from a external balance 400/440, will it work on the 383? Thanks

I pulled a steel crank 400 out of a 4-speed '78 Dodge P/U truck.

Bearings were all std., and had late '77 date on the back, so I'm assuming it was original equipment.

400 with four speeds were supposed to have forged cranks in them. No idea if that really happened or not. There certainly were some 400 motors built with forged cranks but probably not a big percentage.

How about using a 383 forged crank? Same stroke. Just smaller thrust bearing surface.

The 400 I pulled from a 78 Dodge truck, came with a forged crank.
4-speed...Was a pleasant surprise!

From what i know the 400 4-speed cars and trucks came internally balanced with steel cranks. Should pretty much be the same crank as a 383 steel one. I dont think there is such thing as an externally balanced 400 flywheel, for instance.

400s have same rod/stroke as 383 but much bigger piston. 440 has longer stroke/bigger piston than 383. Plus factory balance is pretty loose. If you already have wrong balancer and a vibration I would go ahead an try the other 400/440 balancer all you would be out is your time, because like you said its already wrong.

Was this a balance motor or just a "put together"? Could be a driveshaft vibration.

not a drive shaft problem, does in sitting in park. def. engine related. already tried a 400/440 ext. balancer. vibration was about the same.torque converter has no weights on it and I am assuming it is also wrong. am going to get a new one for 383 external to be sure and I want to replace it anyways.one torque converter fit's 383/400/440 ext. balance, so I would think the same would be true for a balancer, one ext. balancer would fit any ext. 383/400/440

Yes the balancer and convertor/flywheel on any motor are either neutral balance for internal balance motors or are both have to be externally weighted for external. So yes you need a external balance convertor (weighted) and external balancer.

Two other things to think about
1. Someone has internally balanced motor thats why it has internal balance balancer/convertor but then you wouldn't have any vibration.

2. It was rebuilt without concern to balancing the components and no balancer or convertor will put the vibration to rest without taking motor down and taking rotating assembly to machinist to balance.

Oh and if you dont want to buy a new convertor mopar (and Im sure others) sell weight kits with template to make a convertor ext. balance. Ive used one with great success.

383 is original '71 bottom end.just a bigger cam/head work. was a race car since the late 70's. has a high stall convertor that I want to change anyhow. just would like to know if the 400/440 ext balance harmonic balancer that I have will work? or do I have to use the correct pt# balancer that the 72' 383 calls for? I don't want to hunt that one down just to find out the only difference is the pt #.

440 and 400 cast cranks do not use the same balancer. The 71 cast crank 383 uses the same balancer as the cast 400. I have a few. PM me if you need one.

Most 400 4-spd motors had steel cranks. Have had a couple 77/78 400 4-spd trucks with cast cranks and a few with steel. All my earlier 4-spd motors were steel cranks.

yup, I pulled a externally ballanced 'wheel off a 1977 400 cast crank truck engine...worked fine on my 440.