Who has used a 440 crank in a 383 block?

[Kern Dog]

I recently took in a load of parts including a couple of 383 engines and a 440 crankshaft that was supposedly cut down to fit a 383 block.
I'm not 100% clear on how this works. Are the main journal sizes different between the B and the RB series engines?
The longer stroke 440 crank is obviously used to add significant cubic inches due to the added stroke but which length rods are usually used?
I have a set of 440 rods and two sets of 383 rods. I'm guessing that the 440 rods are what people use.
Pistons are another question. They'd be the bore size of the cylinders but are the pin heights different?
I have a rebuilt 383 in a car with maybe 200 miles on the rebuild. It runs great but isn't all that fast.
It is probably a silly question but can a 440 crank actually be swapped into this 383 block without changing pistons?

 

[4mulas]

Main journal on 440 is 2.75 and I think 383 is around 2.625. So they machine the 440 journal down to fit the 383 mains. You’d use 6.76 rod (440 rod)
Pistons are shorter. Yes. Shorter compression height.
No, you can just throw the 440 crank in and not change the pistons and rods as they would drive themselves into the heads and create havoc.
383 with 440 crank gives you 438

I’ve done 451 motors, 400 block with 440 crank and they pull like a freight train. If you’re going to go to the trouble I’d recommend the 400/440 combo for 451.

 

[PROSTOCKTOM]

383/ 400 B-Blocks have 2.625" mains and 440 RB Blocks have 2.75" mains.

B Block cranks have .400" less counterweight diameter than 440 cranks.

So not only do you have to turn the mains down on the 440 crank you have to reduce the counterweight diameter, or at least part of it.

You can actually bevel the 440 counterweights and they will fit, but if you buy an aftermarket crankshaft they just make them .400" smaller diameter.

You're going to need different pistons if you start playing around.

Tom

 

[PROSTOCKTOM]

Main journal on 440 is 2.75 and I think 383 is around 2.625. So they machine the 440 journal down to fit the 383 mains. You’d use 6.76 rod (440 rod)
Pistons are shorter. Yes. Shorter compression height.

383 with 440 crank gives you 438

4.25" Bore x 3.75" stroke gives you 425.58 cubic inches, so you can call it a 426"

Tom

 

[1 Wild R/T]

440 length rod & 1.32 C/H piston 438 CI

 

[Kern Dog]

If I'd only need a set of gaskets and assembly lube, that would be great. If that means a piston swap, it makes more sense only if I was set to rebuild the worn out mill or if I wanted more cubes for racing, neither of which apply to me now.

 

[PROSTOCKTOM]

440 length rod & 1.32 C/H piston 438 CI

Rod length and compression height have nothing to do with the cubic inch and it's not 438"

Tom

 

[4mulas]

Rod length and compression height have nothing to do with the cubic inch and it's not 438"

Tom

A 60 over 383 with 3.75 equals 438.

Pretty sure 1 wild r/t was just answering Kern’s questions by saying you use the 440 rod, a shorter piston with a 1.32 compression height, and at 60 over will yield 438 cubes

 

[1 Wild R/T]

Rod length and compression height have nothing to do with the cubic inch and it's not 438"

Tom

You are right... I calculated it & 425 is correct... 440 Source has it as 438 on their site...

 

[RemCharger]

A 60 over 383 with 3.75 equals 438.

Pretty sure 1 wild r/t was just answering Kern’s questions by saying you use the 440 rod, a shorter piston with a 1.32 compression height, and at 60 over will yield 438 cubes

Bore another 10 thou..... full circle back to a 440.

 

[4mulas]

Bore another 10 thou..... full circle back to a 440.

Haha. Right. But two different behaving engines 4 sure. Short light pistons vs those tanker 440 pistons make for a quick revving big block! They are fun to drive

 

[Geoff 2]

I did this back in the 80s. 438 cubes I used the 383 rods [ R/S ratio is not as favourable with 440 rods ]; had 1/10" machined of crank counterweights.

This was before 'kits' were available so I used 454 Chev pistons & 906 heads. It went very well...
This is the engine Weber carbs on it

 

[Kern Dog]

The one in this car is .030 over...

I'm not that anxious to pull the mill with so few miles on it.

 

[33 IMP]

Frankly, if I was gonna stroke a 383, a 496 would be my choice. Other than that, I'd just leave it a 383.

 

[Kern Dog]

The only thing that was appealing here was the chance to do it low buck. Adding the cost of a set of pistons and rings makes it less so.

 

[Don67Satellite]

This question tickled my brain and I recall Nick's Garage rebuilding a 383 for a RR that he "put a 440 crank into" which made it a 426 cu. in.

 

[Kern Dog]

His math doesn't add up.
The 383 stock bore is 4.25. Add a .040 overbore and it is 4.29.
Bore X bore X stroke X 8 X .7854.
4.29 X 4.29 X 3.75 X 8 X .7854 = 433 cubes.

 

[33 IMP]

okay: bore x bore x stroke x #cyl x .7854 =
383 +.030 + 3.75 crank = 431.6
+.040 = 433.6
+ .060 = 437.7
Standard bore 383 with a 440 crank is 426, of course.

 

[33 IMP]

His math doesn't add up.
The 383 stock bore is 4.25. Add a .040 overbore and it is 4.29.
Bore X bore X stroke X 8 X .7845.
4.29 X 4.29 X 3.75 X 8 X .7854 = 433 cubes.

.7854. Your formula is slightly off. (Well, it is in the first time, anyway)
But I agree. 433 and change.

 

[w.Hudson]

In the late 80's before crank, rod and piston kits were available an old guy used a 440 crank in a 400 block. He used a big block Chevy rod and a Ford piston. I'm not sure
on all the specs and part numbers but at that time the crank was trick. Machined to fit 400 mains and a Chevy rod journal. Another oddity was it was .045 over bore.

I saw it running in his car and it said it ran better than all of his other 440's.

He has since passed on and his grandson has everything but has no money or talent to make use of any of it.

Personally I had a 383 that has standard bore 72 low compression 440 pistons in it with a stock 375 hp cam and 906 heads. 335 hp 383 intake and exhaust manifolds.
It ran very very good for stock parts.