Stroked 400 question.

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Badart

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Is it true that you can drop in a 440 crank into a 400 for 451 cubes? If so what other modifications need to be made other than turning down the mains? Found a local 400/727 combo for cheap and I already have a steel 440 crank.
 
New pistons and RB length rods. Maybe a little clearancing of the counterweights or block depending.
 
The counter weights need to be turned down .200 on a inch to clear the block.
The mains journals need to be turned down on the 440 forged crank to 400 main specs.Rod journals stay the same.
Rod length stays the same.
New KB280 pistons are needed+rings.
Assembly needs to be re balanced
You should,but do not need to,line hone the block
Hot tank block and replace cam bearings and test cam rotation
mrmopartech
 
Use the 440 rods and shorter pistons. It's a better package than the short 400 rod and taller piston.

They are a killer engine package.

KB Hypers
KB280 with 6.76 440 rods
KB215 and 251 with the 6.358 400 rods

The Icon line has a bunch more forged pistons.
 
Like Cracked said, use the 440 rods, i used ross pistons, but they were pricey, i had fun wippen up on 440s with my 451 low deck lol.
 
It's really just a light weight, narrow .060 over 440. It's torquey, yes.
 
Is the machine work any more cost effective than a new crank, which can have even more stroke?
 
375inStroke said:
Is the machine work any more cost effective than a new crank, which can have even more stroke?
Click to expand...

Badart commented that he already had a 440 crank so It would be cheaper to have it modified. If you don't have the crank it's probably cheaper buying one that's already been set up to fit the 400.
Example/ 440 source/ 3.750" stroke (451) crank $600.
 
I am still debating. A local guy has a 400/727 that he claims ran before it was pulled from a truck. It does have a slip yoke for the 727. The motor is complete carb to pan. $400 for everything. I already have 3 motors sitting in my garage. I am running out of space.
 
Interesting, can someone explain why the longer 440 rod makes a better package? Piston weight perhaps?
 
I'm just gonna wait on a stroker. I'm gonna sling a budget 400 together now and save for the stroker. I mean.....doesn't make sense to me to buy a new 3.75 crank when you can get the 4.15 for the same price, the pistons for the same price, punch the block .060" over and build a low deck 505. I mean, if you're gonna do it, DO IT.
 
dustymopar said:
Interesting, can someone explain why the longer 440 rod makes a better package? Piston weight perhaps?
Click to expand...

The longer rod leaves the piston at TDC longer resulting in a bigger "push" from the power stroke. The piston speed is slowed down with the longer rod and makes the engine more efficient. That means more power. Also, there is less side loading on the cylinder walls because of the rod angle. At least that's the word on the street.
 
the manifesto is the best read on a 451 out there. plus the 440 length rod allows a shorter piston meaning less rotating weight meaning a faster rpm'ing motor.
 
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