orangesteve

Hi everyone
This is the first forum that i have joined
partly because i have small blocks and big blocks of the other two, and have now just purchsed my first chrysler motor a 383 just to see what the fuss is about. just by looking at the block and 906 heads now i know.

orangesteve

I was hoping someone would be able to answer a question i have about the bore and stroke,
bore and stroke being 4.280 .030 up and 3.450 stroke.The other strange thing is the pistons say .040 up
which says to me perhaps offset ground or some sort of stroker.
Any help or info on this would be greatly appeciated.
Cheers.

TVLynn

If the pistons say .040 IT has already been bored. the .030 ? may be that the crank has been turned .030 undersized already ??

orangesteve

Hi thanks for the reply
What i don't understand is that 4.250 is standard why would there be 040 on the piston when my callipers say 030 up. 040 would be 4.290 i would of thought. The only pistons i can find that match the 4.280 @ 040 up are L4 Cummins diesel Correct me if i'm wrong but an undersized crank, lets say -.020 would take +.020 bearings so therefore not effecting the stroke?


I know enough to get me into trouble

TVLynn

Could be your measurements ? Measure the piston opposite (90deg)the piston pin just below the ring groove. the piston skirt is smaller to allow for expansion,, it will measure smaller than the cylinder bore. Are there any numbers on the piston or rod bearings

Mr.4spd

The stroke doesn't change because equal material was removed from the entire journal. If the crank was offset ground then you would have an increase of stroke.

orangesteve

Yep, thats what i figured.
Cheers for your reply too, any idea on the stroke or stroker mistery?

orangesteve

I have'nt been able to look under the sump for a couple of days due to work related issues nor have i taken the caps of just yet but a good idea tho, i might be able to see if its been offset ground if i drop a couple of rods.
My idea is atm to see what i'm looking at and which way to go (stroker or mild rebuild )
First i want to try and establish what i have without disturbing too much looks like i might be able to rering it, however first things first.
Ohh and it has got .040 on every piston.

rickyr

welcome to the forum

Gorts 5th

383 B block bore 4.250 is 3.380 stroke and 383 Rb is 4.030 x 3.750
according too a book we got

orangesteve

Thanks Rickr
That GTX is sweeet!!

rickyr

thank you

orangesteve

Yep thats what i understand too, stock b block 383= 4.250 bore and 3.380 stroke. A book where it is written is usually good confirmation, thanks Gorts 5th.
Thanks to http://www.geocities.com/musclemopars/brbblock.htm
This is where i got the info on stock bore and stroke,
with the figues i've got, i worked it out to be 397 cubes, does anyone know if this sounds right early stroker perhaps?

orangesteve

O.K just managed to check the rod journals and they came up @ 2.365 or there abouts.
i'll check the rod length tomorrow.
Any ideas? Anyone

Gorts 5th

The book say's B> R.B 2.380 rod journal and main's B. 2.625 , R.B 2.750

orangesteve

Awesome that 2.380 was the figure i was looking for.
So this would mean that the bearings would be undersize .020 seeing as tho i used the verniers , Now, for the stroke and rods..

orangesteve

Abandon post!!!
Sorry people, how do you say, Oh S#!?.....
It appears "someone" assumed a zero deck height.
Here is as stands:- Bore =4.290 .040 up (combination of in the dark and carbon build up ) Stroke=3.380 Rod length=6.354 Journal=2.360 .020 under.
I can't believe i ****** up so badly ,Once again so sorry.
It brings me back to an old guy and one of his cliche's "90 % of all stuff up's is due to assumption"

So in short a standard 383.

orangesteve

Abandon post!!!
Sorry people, how do you say, Oh S#!?.....
TVLynn you were right "someone" needs to check their measurements
It also appears "someone" assumed a zero deck height.
Here is as stands:- Bore =4.290 .040 up (combination of in the dark and carbon build up ) Stroke=3.380 Rod length=6.354 Journal=2.360 .020 under.
I can't believe i ****** up so badly ,Once again so sorry.
It brings me back to an old guy and one of his cliche's "90 % of all stuff up's is due to assumption"

MReeves

Welcome to the forum... I have been following your thread... No reason to abandon it... I was just proud of how many answered your call for help with thoughts and suggestions.... Just shows how great a group we have here... That's the Mopar way!!!! Also, don't forget to check out the Mopar of the Month contest......

orangesteve

Thanks man
Its just that i'm a little embarrassed to say the least, when really i should have checked and double checked before "one inserts foot into mouth" and goes and starts a thread that has no purpose.
Although i do really appreciate all the help and advice i've got , so yes they are a thoughtful and helpful lot ,and i'd like to say a big thanks to all who has posted so far

orangesteve

Hey MReeves
i was looking at your profile thats a nice challenger!
I have another post going in transmissions on the A518 seeing as tho your in the drag scence would you know anything on doing a full manual?