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-   -   383 steel crank or 440 cast?? (http://www.moparchat.com/forums/showthread.php?t=61758)

TrxR 11-07-2002 02:23 PM

383 steel crank or 440 cast??
 
Ive been searching for a big block for my 87 Dakota 2x4 and I came across a 74 440 out of a motor home with 15000 miles and also a 68 383 2bbl carb which has never been bored . Which would be the better build?? I was leaning toward the 383 because of the steel crank and the deck height is lower ( fit easier) . Either way im going to run eldebrock aluminum heads. Also is there anything required to run a RB heads and intake on a B block??

Mills 11-07-2002 02:28 PM

The 383 would be a better fit in your 'Dak. The 440 would give more power and torque, but fitting it would be harder. There is no difference b/t RB a B heads. You would need to put the correct intake on either engine - B on B, or RB on RB. The only exception would be the MP Stage VI heads, which are designed for B blocks w/ RB intakes.

71383bee 11-07-2002 02:36 PM

A RB intake will not fit on B block. There are adaptors to get a B intake to mount to a RB, but not the oposite.

As far as your motors are concerned the cost to build a 440 or a 383 is practically the same. The cast crank can handle up to 500 hp. Are you sure the 383 2Bbl crank is forged? Your right about the 383 fitting easier.

I would want to know the condition of the castings and choose the one with the lower casting index. The casting index is the raised casting numbers that are cast into the block on the side below where the heads mount. The last 2 digits are separated by a hyphen and identify the casting index. The higher the number the more cores were made to create the cylinder bores. A perfect CI is a 2 (1 per side). The worst is a 10 (2 per side and 8 additional cores).

TrxR 11-07-2002 04:57 PM

were some of the pre 74 big blocks cast cranks?? 71383bee what side of the block are these casting numbers ??passenger or drviers and is this the big long casting number?? What do I look for a on a assembled 383 or 400 or 440 to tell me wether its cast or not??

P.S I think the 383 was out of a 68 monaco

71383bee 11-07-2002 06:54 PM

All cast cranks are externally balanced so their harmonic dampners are usually very large and look out of round. There is nothing wrong with using a cast crank as long as it is machined properly. They can take a decent street build (about 500 hp). For heavy duty track or drag racing I would prefer a forged crank. I think 72 and up big blocks all had cast cranks. Pre 72 at least all of the hp engines came with forged cranks. I can't speak for the nonhp 440's and 383's.

To be honest i forgot which side of the block the casting index is, but it is not hard to miss if you have the engine out. It is a long 8 to 10 digit number that identifies what block it is and the numbers are about 5/8" tall and stick out about a 1/16" from the side of the block.

The casting index is not a huge deal if you are going for a mild street build. No matter what it should be sonic tested to be sure. I seem to remember someone on this board who posted his block id and he had a real high casting index. Something like 8 or 10 and later he posted about having to sleeve 4 cylinders because his walls were too thin. The index is just a useful tool in determining the final goals of a particular engine. My 383 is a casting index of 6 and it was a true HP engine.

DAN-THE-MAN 11-07-2002 07:34 PM

has anyone ever had or known someone with a bb mopar forged or cast to fail

lenweiler 11-07-2002 07:58 PM

Just one failure, and I'm not sure if it was driver error or the crank.
I do know that the Mopar cast crank can stand up to large amounts of abuse. I've personally watched a madman pound his '74 4speed runner with a cast crank 400 time and time again. Not a 440 but the same material.

dave571 11-07-2002 11:52 PM

ALL 383's are Forged cranks. They were replaced with the cast 400. I have heard of a 383 getting a cast crank as the 400's were fazed in, but have never seen one.

Not all cast crank engines are externally balanced. Big blocks, yes, but cast crank 318's and 273's are internally balanced.

Dart 11-08-2002 09:49 AM

Cast crank 318 and 273? Not where I am from. Never seen one of those. 360 is cast crank.

Dart 11-08-2002 09:52 AM

One thing to remember about a motor home motor. They usually see a lot of heat and are normally worn out around 75-85k. The heads are sometimes different and the whole front of the motor will need to be replaced with the car stuff. Tha cast crank 440 is fine to build. You could always buy the block and round up a forged crank...just an option.

dave571 11-08-2002 11:31 PM

318's and 273's have been cast cranks since at least 1969. That in mind, if you've seen 318 made since 1970, you've seen one with a cast crank.

The original engine from my 69 dart was. Some were split production in the late 60's.

Dart 11-11-2002 12:58 PM

Maybe in Canada, but not here. I haven't seen a cast 318 or 273 crank.

dave571 11-11-2002 11:19 PM

I don't think there were any "Canada only" engines in the 60's and 70's.

Even 340's were cast by 72. I've started another thread on this topic, so we can see if anyone knows for sure when the cast 318's started production.:confused:


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