440 rods in a 383

[68mopar]

Hi Everyone,

Apart from finding the right pistons what other issues would I run into putting 440 rods into a 383 and what C I would you end up with. Also has anyone run Aluminium rods in a street engine.

Thanks

[Chryco Psycho]

Alum rods have a very short life span , basically 50 - 100 MAX trip down the 1/4 mile , I do not recommend them for street use
 by using 440 rods in a 383 with no other changes you will have a 383 CI engine , rod length will not affect displacement , you will have a much higher rod ratio though @ 2 -1 instead of 1.78 approx , I assume you want to build a stroker so you would need to use Both the 440 rods & a different stroke crank like the 440 with a 3.75 stroke or longer   

[moper]

What he said. Aluminum rods have no business in a street engine. The 6.768 rods are a bit heavier too, so balancing will be harder (read as more $$). The swap isnt worth anything unless you do go bigger inches. 383+.030 will go 432 or so inches.. 4.28bore x 3.75 stroke. A 383 is just a destroked 426.

[moparnut]

A 383 is just a destroked 426.

Is that true?I never heard that,thanks

[Killer_Mopar]

Is that true?I never heard that,thanks

Not really true, when the 383 has the same stroke of a 426 then it has the cubic inches of the 426. However, the 426 is still a RB block and has a higher deck height and the mains are larger, so they are not the same engine. They could be the same engine if a rare 383 RB block is used....

[Challenger6pak]

The general evolution of the B motor is 350, 361, 383, 400.  The RB evolution is 413, 426, 440. 

[moper]

Like they said, 383 is B, 426 is RB, but strickly speaking bore and stroke, a 426 is 4.25/3.75, the 383 is 4.25/3.37. I should have clarified..lol.

[68mopar]

Thanks for the info guys, I had no idea that nothing changed (displacement wise) by just changing the rods. Looks like I might have to start searching for a 440 crank as well, and my aluminium rod idea is out the window also.

Thanks again

[Challenger6pak]

If you want to build a large cubic inch B motor use a 400 block.  In the long run it might be cheaper depending on what you want to do to just start with a 440. 

[68mopar]

Thanks Challenger6pak, I've looked into that as well. But living in Australia has it's limitations when it comes to mopar stuff. 400 block are a rarity and I'm also on a massively small budget after my girlfriend and I brought a unit 6 months ago. It's looks like my engine might need a rebuild in the next few months and I was looking for a cheap option to get a few more cubes out of it. Might just go for a standard rebuild thought with a bit more compression.

Also what is the maximun compression ration I should go for if I only ran 98 octane fuel with cast iron heads

Thanks

[Chryco Psycho]

approx 10:1 , depending on cam used with 98 octane fuel

[moper]

440 Source has a kit for using the 383 block and getting a 457" from it. No oil ring support rings, and not too bad a rod/stroke ratio either. You would need to clearance the crank counterweights (cut down on the lathe), and do some clearancing on the block.

[70RAGTOPR/T]

I agree with Mopar.  Use 440 Source.  I'm building a stroked 383.  I would use the 400 but I have two 383 blockes in my garge.  440 Source has everything.  I think the cost was around $1350 w/ upgrades.  I provided the link below.


http://www.440source.com/