Why would you not put a 383 forged crank in a 400 block?

B/c it's so easy to put a big stroker crank in one. That's the only reason I know of.

Seriously though...there isn't a reason really. Just have it balanced for the heavier 400 slugs, use the internally balanced damper and flexplate, and should be good to go.

Early 400s that came in 4 speed cars had a steel crank, most likely leftover 383 cranks that were rebalanced.

Works fine. I have a 400 engine for my Duster that uses a 383 forged crank with Hemi rods and stroker pistons. It is a nice combo that really winds the clock.

Makes for a VERY strong platform to build on. I would guess one of the better cheaply built power adder combo's you could do.

Look back at that orange Challenger built way back by I think SD Concepts, it had a 400 block/383 crank with a Procharger making in the 1100 hp range IIRC, think it even had B1 heads.

I wouldn't be surprised if the '68-'69 383 piston weighs about the same as a 400 piston...400 is larger in diameter but the 383 has a higher compression height.

Hollander shows the 383 and 400 forged as a direct interchange.

I did a 383 crank in a 400 block, internally balanced now.

We have a 383 crank in my sons 400. And of course we had it internall balanced. Ron

DUH!!!!!!

How many times do we have to go over this?

In the late run of 383s, they used a cast crank with external balance. When the 400 came out, the cast crank versions used THE EXACT SAME CRANK AND EXTERNAL BALANCERS. Meaning that what was attached to each crank was THE SAME.

The same thing happened with forged cranks. The EXACT SAME CRANK went into forged crank 383s and 400s. Chrysler kept piston weights the same to allow them to do these kind of swaps. Shoot, when the 273 came out it had a special thickwall pin so they could use the same crank as the poly 318s. Chrysler was a company that was strong on engineering and that means they were very good at figuring out what they could get away with.

Plus, the factory balance jobs were nowhere near as accurate as people think is necessary nowadays. AND, people who bought Mopars didn't flood the dealerships with complaints about the engine vibrating.

All of this "you have to balance because there's an 11 gram difference in piston weight" horsepoop is just that.....horse poop.

Now I agree that perfection is better than nonperfection. But how much money is it worth?

There is a board member who I respect as having raced a lot of smallblocks who replaced his factory 318 pistons, 591 grams, with KB 167s, 507 grams, and ran the engine and he claims it didn't run any rougher. I believe him.

Ever hear of overbalancing? Underbalancing? They do it on purpose to race engines. What we think of as God's truth about balancing a V8 is mostly what was figured out to work about as well as it could work. It is empirically driven, not deriveable from mathematics.

For one thing, piston motion is NOT a perfect sine wave.

R.

Chew on that!

I think the OP is asking this since most 400's are cast cranks and most 383's are forged cranks. Ron

Im still amazed at how many mopar guys still insist that all 400 cranks were cast..

I know all 400's were not cast but I do agree most of the ones you see are cast. Or I know most of the 400's I see are cast but of course they are forged 400 cranks out there just not alot of them. Ron

Answer to the original question - No reason why not, people have been swapping them back and forth for decades. Reread my rant above, which came after a long day at work answering dumb questions.

R.

That was not directed at you Ron..!!!