440 crank in a 383

[Shorty Thompson]

So,,,,,,, I punched my 383 out as about far as I care to. I got a 440 crank that's had the main journals turned to 383 specs. Now I know I just can not put it in and expect it to spin freely without hitting something. Is it worth the effort, or is it better off getting an after market crank and just leaving the block in stock format?

 

[nitro_rat]

The old way was to offset grind the rods to take a big block Chevy rod and then have custom pistons made. 440 Source has all the stroker information on their site. They put together complete rotating assembly kits that will mostly just drop in...

 

[autoxcuda]

It looks like 440 source makes a rod and piston combo for stock rod journal and 3.75 stroke?

Stroker Kits-store.440source.com

If you want to make sure everything is compatible; go with a 440 source balanced kit with 438” or 496”

 

[Geoff 2]

When I did this, I machined 0.100" off the bob weights to reduce rotating weight.

 

[Kern Dog]

This topic has been on my mind too.
I have a 383 that I rebuilt in 2020. In these 5 years, it still has less than 250 miles on it. It runs fine but lacks the torque of a longer stroke engine. In fact, I have a 360 in another car, a 67 Dart. The engine in that has the same cam specs and the 360 gets the jump on the 383 every time.
Last year I took in some parts including a 440 crank turned down to fit a B block. It came with rod and main bearings too so the thought of going from a 388 to a 431 for just the cost of pistons, rings and gaskets is tempting. I'd add 43 cubic inches for a lot less than it usually takes.

 

[Lefty71]

Now I know I just can not put it in and expect it to spin freely without hitting something.

No.....i think you can. Problem starts at around 4.25 stroke, IIRC. Or is that only in 400 and 440 blocks?? The oil pickup will be the first challenge.

 

[kramer]

The 440 RB crank in a 383/400 B engine the OD of counter weights usually have to be machined down or the edges of the counterweights have to be heavily chamfered in order to keep from hitting the block or to get a minimum clearance and as stated before the mains journals have to be machined down on the 440 RB crank to 383/400 B engine size or another option is to line bore the mains of the 383/400 B engine out to 440 size and use 440 main bearings.