Does anyone have a source for a good uncut steel crank for my 69 400, want to put it back to original specs and am having a hard time locating one. Only thing i have found so far is having a billet crank made but kind of costly and long delivery.

 

A "steel" crank would not have been "original spec" for your 69. The forged long stroke cranks were only used in the early part of the 1968 model year and only in 455s (though the G-block 400 uses the same crank as the 455). Your original crank would have been a cast nodular crank. Any 1968-76 400 or 455 crank will work and be correct.

Edit: To avoid confusion, note that the 1975 400 motor is not an Olds motor, it is a Pontiac-sourced motor, so obviously that crank does not work.

 

You really should not get hung up on finding an uncut crank. As long as the crank is machined by a compitent machine shop, it really will not affect it's performance. You're not going to want to reuse your original bearings anyhow. You could use a 455 crank but I think the rods, pistons and flex plate will be different. In my opinion you should upgrade to the 455 after all there is no replacement for displacement. It will be a lot easier to get off the shelf pistons. I'm pretty sure all the 400 and 425 cranks were steel and most 455 cranks were nodular. I had a 455 steel crank and sold it. They are very heavy and hard to find. Unless you're building a race car, the nodular crank should be fine for you. You may want to start a thread in the parts wanted forum and be sure to list your location.

 

Sorry, that is not correct.

To clarify, ALL 1968-69 G-block 400 motors and ALL 1968-76 455 motors use exactly the same crank, rods, balancer, and flexplate/flywheel. The pistons are different due to the different bores (3.890" vs 4.125"). All except the rare early 1968 forged cranks are cast nodular. All are functionally interchangeable (with appropriate balancing for piston weight differences).

Similarly, the 1965-67 short stroke 400s and 425s all use the same crank, rods, balancer, and flywheel/flexplate. Obviously these are different from those on the long stroke 400 and 455. All short stroke cranks are forged.

 

Dave
There's several members here with spare parts including crankshafts. Since the 455 crank will also work you shouldn't have any trouble finding one. I'd encourage you to create a parts wanted thread. I'd also include your location so if there's someone who has one within driving distance that would be better than having one shipped across the country.


John

 

I would use the original crank and have it ground. You cant get more original than that,if this is the crank that came in the engine and its number matching.If the Crank is toast just get another N crank that was made close to the time of your engine. Is this for a 400G block,and did the engine spin a rod bearing.This engine was bad for this.