383 crank in 400 block?

9073 Views 22 Replies 16 Participants Last post by Brent, Aug 9, 2012

Brent

Discussion Starter · Aug 2, 2012

K guys, has anyone here used a 383 crank in a 400 block, using bearing spacers?
Similar to what you would do destroking a 400 with a 350 crank...
I'm asking cause I want to build a 406, but recently picked up a steal 4340 383 crank and H beam rods for next to nothing and was thinking of using the spacers to build a nice healthy sb 400...

1 - 20 of 23 Posts

BD's65ss

· #2 · Aug 2, 2012

Maybe I'm off, but I swore a 383 crank IS a 400 crank. If its not, I've got some homework to do.

Hopefully someone else chimes in, cause I'm in lala land right now.

the FLYER

· #3 · Aug 2, 2012

400 w350 crank = 377

350 w400 crank = 383

there's no such thing as a 383 crank...

the 400 crank mains are ground to 350 specs to make the 383. on a 400 with a 350 crank you'd either run spacers or buy a 400 w 3.480 stroke and install it...

Ryan V64SS

· #4 · Aug 2, 2012

Do some research on bearing spacers and you will probably find that getting the right crank is the best move.

Ryan V64SS

· #5 · Aug 2, 2012

the FLYER said:
there's no such thing as a 383 crank...

from the factory, no but Since the factory never made a 3.75 stroke with 350 mains any aftermarket crank made this way 99% of the time is going to be slammed in a 4.030 block and that equals a 383:yes:

BZ65

· #6 · Aug 2, 2012

There is such a thing as a 383 crank.http://www.chevroletperformance.com/_res/pdf/installation_guides/small_blocks/zz383/ZZ383_Engine.pdf

johnretired

· #7 · Aug 3, 2012

Mopar has made millions of 383 cranks!!
What he is asking is about running a 350 sized journal in the 400 block. Racers have done this for years with few issues.
Some even use undersized bearings with 350 bearings.

Pandora's Box

· #8 · Aug 3, 2012

Brent said:
I'm asking cause I want to build a 406...

A 406 is just a 400 block that is bored.030".

rquad

· #9 · Aug 3, 2012

BZ65 said:
There is such a thing as a 383 crank.http://www.chevroletperformance.com/_res/pdf/installation_guides/small_blocks/zz383/ZZ383_Engine.pdf

No offense, but that's a misunderstanding. A "383 crank" will yield different cubic inches depending on the block it's put in, and the bore of the block. The way to get a 383 SBC is to put a 400 crank in a 350 block that is bored 30 over, and the crank has been machined to fit the 350 journals. Put that same "383 crank" in a different block with a different bore and it will give you different cubic inches.

So, there really isn't a 383 crank per se, but it would be a crank originally intended for a different engine that has been machined to fit the 350 block.

Incidentally, if your 350 was totally stock and required no overboring, that "383 crank" would give you 377 cubic inches. So, a crank doesn't have cubic inches associated with it--it's just part of the overall engine equation.

Pragmatist

· #10 · Aug 3, 2012

the FLYER said:
there's no such thing as a 383 crank...

http://www.crateenginedepot.com/Crankshaft-383ci-4340-Steel-12489436-P9799.aspx
Just to throw ink in the ointment.

sbc1320

· #11 · Aug 3, 2012

Pragmatist said:
http://www.crateenginedepot.com/Crankshaft-383ci-4340-Steel-12489436-P9799.aspx
Just to throw ink in the ointment.

Can that crank be used with fenderwell headers?

sbc1320

· #12 · Aug 3, 2012

Brent said:
I'm asking cause I want to build a 406, but recently picked up a steal 4340 383 crank and H beam rods for next to nothing and was thinking of using the spacers to build a nice healthy sb 400...

Yes you can if you use the bearing spacers.

luepke75

· #13 · Aug 3, 2012

johnretired said:
Mopar has made millions of 383 cranks!!
What he is asking is about running a 350 sized journal in the 400 block. Racers have done this for years with few issues.
Some even use undersized bearings with 350 bearings.

Sounds like he wants to use a 400 crank machined to fit a 350 block in a 400 block.

luepke75

· #14 · Aug 3, 2012

rquad said:
So, there really isn't a 383 crank per se, but it would be a crank originally intended for a different engine that has been machined to fit the 350 block.

Yes a 400 crank

Click to expand...

sevenzeronova

· #15 · Aug 3, 2012

luepke75 said:
Sounds like he wants to use a 400 crank machined to fit a 350 block in a 400 block.

Sounds that way

just get a 400 crank??

carcass

· #16 · Aug 3, 2012

Semantics,
Everybody knew what he was talking about, a 383 crank is a 3.75 stroker crank with 350 sized main bearings.

Yes you can use the crank with bearing spacers.

I call it a brody, you call it a donut.

On the construction site theres always some idiot correcting someone elses grammer in the porta potty. Good Grief.

luepke75

· #17 · Aug 3, 2012

sevenzeronova said:
Sounds that way just get a 400 crank??

Would be easier and cheaper.:yes:

bowtie0069

· #18 · Aug 4, 2012

a 383 crank is a 3.75 stroker crank

Not the factory 383; they use a 3.800" like I run in my 410" (.020" over 400) or my old 414" (.030" over 400)

The Big Al

· #19 · Aug 4, 2012

Yes, my Lunati 3.750 crank has 350 mains in a 400 block

I used spacers for mains. If your line bore and bearing crush is correct you will have zero issues.

Main spacers have been used for years. In the old class racing days of small Cu, we used them a lot with Small journal cranks in later model larger journal blocks.

You can see the spacers.

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onecarnut

· #20 · Aug 4, 2012

In a June 1997, Hot Rod Magazine did an article on using a 400 block with a 327crank and 6.2 rods from a ford inline 6.

This destroked engine had high compression but could run on low octane gas.

Hope this link works:

http://www.airflowresearch.com/articles/article003/A3-P1.htm

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