Technical 70 383 magnum b or rb?

Doing a 70 383 magnum for my 41 Desoto buis cpe.
Found a 383 magnum numbers correct.
Stamped HP.
I have been under the impression that the 383 magnum is a RB block.
Picked upa electronic dizzy for it and the shaft is about 3/8" too long.
So . is the 383 magnum 1970 a b or RB block?

 

B

 

^X2 I believe they did make a 383 RB motor for a couple of years 59 -60.

 

You got a good one. That 383 will outrun a 440 if it's done right. Oh by the way It will outrun a 427 Camaro for the money.

 

Nope the 361-383 & last was the 400 all B blocks HP stands for Hi Performance. The RB stands for ( raised block ) and is 440 CI

 

I beg to differ if the "Nope" was directed at my post. This is just one of the many articles on the 383RB.

"Not to be confused with the 383 B engine, the 383 RB had a 4 1⁄32-inch (102.4 mm) bore (with the long stroke of 3.75) for a displacement of 382.9 cubic inches (6,275 cc). It was only available in 1959 and 1960 on the US-built Chrysler Windsors and Saratogas; one of Trenton Engine's lines had been converted to the new RB engine (to make the 413), and demand for the 383 B engine was too high for the remaining line. The solution was to create a 383 RB to fill the gap until the plant figured out how to quickly switch from one block to the other."

The OP does not have this motor. I just thought it was cool that Chrysler made some odd ball motors back in the day. They also had a 350 B and it was only available for 1 year.

 

....but not if the 440 (or 427) is done right.

 

it was probably one of those 383 six pak hemis...You know, the special one, that only uncles could order...

 

yes...the first 383's were RB's.....59-61.....

 

You could put a set of Stage V hemi conversion heads on a B motor and have a close cousin.

 

I gotta say...I have built a few 383 Mopars, I have built a few 440's. I have even built a couple 427 chevies. Its pretty fair to say I am even a big fan of 383 Mopars.
Any stories about 383 magnums out-running sq. port 427's are just that...stories.

 

You have a distributor for a 413, 440 or as others have pointed out a 2 year only 383. As long as it's not some cobbled together aftermarket piece and is a Chrysler electronic ignition distributor you can just swap out the the lower shaft from a "b" 383 or 400 big block distributor and you"ll be good, it can be a points type or electronic distributor the lower shafts are the same.

At this point in time the HP stamp just means it probably had the snot kicked out of it early in it's life, or some little old lady drove it to church on sundays and bingo on tuesdays then sold it to some kid 20 years later that beat the snot out of it. Or so the story goes....

 

From some of the info I have read. It says that the 68-70 383 magnum is a RB engine so apparently this article was wrong. It Definately has the short shaft dizzy in it indicating a b block??

 

you might not be able to believe everything you read.

Which of these blocks is more like yours? look at the number stamp pad location, look at the deck height relative to the water pump mounting boss, look at how much room there is between the end of the valley pan gasket surface, and the outer bolt hole for the valley pan retainer.

B block:



RB block:

 

Throw that book away.

.

 

There's some hidden love in my brain for the venerable Mopar wedges, and like any engine I'm sure you can throw enough money at it to beat anything with a proper marriage of support like trans, gear, weight, blah-blah-blah. My Mopar would be a late 60s variant with a snotty RB dressed to look like a 426 wedge. All of that aside, how friggen kool is this place? I mean good info, pictures to compare, ideas to make things work that will actually work. Awesome to the 383rd power...

 

Thanks for the pics. Mine is Definately a B block. The stamp pad is flush with the block deck. The info I saw was on allpar of all places. So was there a 68-70 383 RB?
I think I'll just replace the dizzy shaft with one from a b block. Problem solved. Thanks again.

 

My grand mother had a '68-'69? Polara 440 as I remember. 4 door big car with a small bore long stroke 383 RB engine. I did a valve job on it years ago. Later 383 had a larger bore, shorter stroke and were B blocks. Maybe 63 or so. i really don't remember. CHP bought the same cars that year.

 

AS has been stated ,the RB 383 was an odd ball you will probably never see. The low block 383 is a great engine, I won't weigh in on what is fastest ,just say let your credit card be your guide.

 

Why did mopar make it so confusing.
But now I can tell the difference.
Anybody in the market for a RB accel dual point dizzy. ?

 

Where did you read THAT??!! On the HAMB?

 

Of course if I built a 383 with a tunnel ram, heavily ported heads, monster flat tappet or roller, 12/1 and backed it with an 8" converter, 4.88s, and slicks yes, it would thump a stock 427 sq. pt. with 3.73s and f-70 15 polyglas wideovals. Then do the same stuff to the 427...
I really like 383's too, and have built some strong ones. I wont say how I would do it, it will be in conflict with the usual HAMB stuff...Like RB 383s coming stock in late sixties c-bodies for instance...

 

Don't throw it away.....Someone else might find it. Pour gas on it, burn it, stir the ashes, pour more gas on it and burn it again. Make sure there are no traces left...

 

I think I saw that on the allpar site

 

GOOD GRIEF!!! Maybe it was a typo?

 

You can use the RB distributor in a B block if you machine a small ring spacer to raise it up. MaMopar actually offered this spacer in the Mopar Performance catalogue...P3690275....

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