383 Cast of Forged crankshaft??

[two4ruff]

I have a 383 date coded 3.30.66. That said it "should " have a forged crank. Unfortunately I found the head were swapped to the newer 8462846 heads. I tore the motor motor apart and I'm not sure how to distinguish the type of crankshaft. I'm concerned someone switched it out.

Thanks!!

 

[RemCharger]

It's cast. If it doesn't say 400 on it somewhere, it's probably out of a 71 383 2 bbl

 

[two4ruff]

It's cast. If it doesn't say 400 on it somewhere, it's probably out of a 71 383 2 bbl

That's what I was worried about. Appreciate the help.

 

[Photon440]

Should also have external balance damper on it if cast. Should still be safe at 6,000 rpm and 450 hp.

 

[gkent]

BEST way to tell ... a "cast" crank will have thin parting lines from the casting process 1/8" or less. A "forged" crank will have wide parting lines around 3/8" to 1/2"

 

[RemCharger]

The cast numbers and symbols are a bit of a giveaway as well

 

[1968rt]

Take a look.

 

[1968rt]

Late 71 2 bbl 383s were the first cast big block cranks

 

[two4ruff]

Ok, so it looks like the crank is cast so not the original for the 1966 block. Does the cast crank engine use a different harmonoc balancer, flex plate and torque converter than a forged crank?

Thanks,

 

[33 IMP]

Different balancer and converter weights added. Flywheel if stick is also counterweight.
There are cut-away flexplates so you don't have to use weights on the converter, but the stock flexplate is normal/neutral balance.

 

[two4ruff]

Appreciate all the replies. Bought a 69 Road Runner a couple years ago from a guy I know. He had the engine and trans from someone else. Said his friend told him it was a good combo. Not recently rebuilt but ran good. When I got the car done and fired I had a shake. I suppose that's due to the wrong balancer and flex plate. Pulled it all back out and now I guess it's rebuild time. Sucks that someone snached the forged crank.

 

[RemCharger]

Appreciate all the replies. Bought a 69 Road Runner a couple years ago from a guy I know. He had the engine and trans from someone else. Said his friend told him it was a good combo. Not recently rebuilt but ran good. When I got the car done and fired I had a shake. I suppose that's due to the wrong balancer and flex plate. Pulled it all back out and now I guess it's rebuild time. Sucks that someone snached the forged crank.

Or more likely it was toast from spun bearings or such

 

[Lefty71]

Appreciate all the replies. Bought a 69 Road Runner a couple years ago from a guy I know. He had the engine and trans from someone else. Said his friend told him it was a good combo. Not recently rebuilt but ran good. When I got the car done and fired I had a shake. I suppose that's due to the wrong balancer and flex plate. Pulled it all back out and now I guess it's rebuild time. Sucks that someone snached the forged crank.

You def need to fix the mistakes. An original forged crank should be easy to find.

 

[Curiousyellow71]

We have a 71 383hp out of a charger that also was born with a cast crank. We ran a convertor in it that was off a 400 that had the proper weights. Of course we ground those off because all 383s have steel cranks... according to the magazines we read (before the internet) ....yes, it vibrated.
Really nothing wrong with cast crank with the proper balancing. Back then it wasn't made in china!