400 crank?

[Krooser]

This crank is in what I thought was a GM replacement engine...is this a 400 crank?

[rustbucket79]

If the crank has a dowel and the flexplate has a counterweight (along with the dampener) that’s a start. Is the block a 400 block?

[chevyfreak]

Like said check for external balance weights to flexplate and damper. Going by the shape of rear crank flange doesnt work, the 350 looks the same.
The 400 also had a necked down shaft for oilpump, but thats only in the 400 block because of bigger mains.
Easiest to verify is to measure stroke if heads are off.
Can also check on crank casting number,

Chevyfreak.

[Krooser]

Well I doubt it can be a 400 crank since it's a Mexican block... and heads. Casting #249 as far as I can tell. Cast steel.

Not very familiar with the later model Chevy stuff. Got a couple 1182 forged cranks in stock but those have the round crank flange IIRC. What threw me was the shape of the flange... looks like the bolt on weight you needed to run a LJ 350 crank in a 400 block.

Bought this engine just because... it's going to a swap meet Friday and I just need to know what I have here. Trying to be honest about it's parts and condition.

Thanks.

[chevyfreak]

Any other numbers on it?
Should be 4 , 6 , or 7 digits for 2pce seal cranks.
Most probably 3.48 stroke crank.
From what i remember that shape of rear flange is on 3.48+ stroke cranks.
The shorter stroke have round with some or no notches. Depending on stroke.
I have never had a crank cast no. being wrong but seen the rear flange shape being changed.
Hopefully someone else have more info and give more insight.
Will include a numbers list as well. Hope its readable.

Chevyfreak.

[Krooser]

Thanks