engine block machining

[Ryan.C]

I have a low miles 1969 383 short block, pistons 0.005 in the hole. my plan was to put a set of ported stealth heads on it and run the short block as is. I was talking with the local machine shop about the heads and the machinist says it is imperative that the block be line bored, decked and bored to true everything up. are mopar blocks that poorly machined from the factory that they are not to be trusted. Is this machinists doom and gloom stance on factory mopar iron warranted.

opinions please.

[JB400]

If this is a racing engine, then I would tear it down and do everything recommended.  If this is a street cruiser and there is no significant ring ridge or pits, and the bearings are still tight, I see no reason to tear the short block down to do what he wants to do.

How well did this engine run before you tore it down?

Kinda sounds like he's looking for some more money.

[Scaregrabber]

If the short block is still together I would check the deck heights at all 4 corners. It's most likely just fine to run as-is on the street.

Sheldon

[Ryan.C]

This is going to be a fair weather driver, with the occasional 5500 rpm 1-2 bang shift.

The ring ridge at the top of the cyl. is just barley felt with a fingernail. I pulled the oil pan a few minutes ago and the bottom end is looks good, at least nothing obvious from a visual inspection. I think to be on the safe side ill plasti-guage the crank and rod journals. thanks for the feed-back thus far.

[justcruisin]

If you want to spend the money get it machined, that is best. BB mopars are often out of wack, the virgin deck on my 440 was 0.007" out from one end to the other on one side, I could rock the head (new eddy) when I laid it on the block. In saying that the engine did 160000 miles like that with one rebuild in that time. So if the head appears to sit flat and its not a race build I don't think I would get to concerned.

[Ryan.C]

thanks guys, ill do some measuring and go from their.

[Scaregrabber]

If the bearings all wore nice and even, his linebore theory is not necessary, that will save having a sloppy timing chain afterwards.

Sheldon

[flyinlow]

Find another machinist.

[Cooter]

Most likely the machinist is recommending 'truing up' the block for longevity/warranty purposes. If he doesn't true the block up and your buddy has a problem with it, what's the first thing you/your buddy are gonna think??

Yep, that machinist ain't no good, and I wouldn't take my lawnmower to him. Yes, many BB Chryslers fell victim to Mass production tolerances. Not too many were machined to today's standards. Hell, even the brand new Stroker kits from Eagle say they are machined/balanced, but take them to a machine shop and Most times, they need a little tweaking. Doesn't mean they are junk, just mass produced to keep costs down.

[Challenger340]

I have a low miles 1969 383 short block, pistons 0.005 in the hole. my plan was to put a set of ported stealth heads on it and run the short block as is. I was talking with the local machine shop about the heads and the machinist says it is imperative that the block be line bored, decked and bored to true everything up. are mopar blocks that poorly machined from the factory that they are not to be trusted. Is this machinists doom and gloom stance on factory mopar iron warranted.

opinions please.

Yep...IMO...they were Machined like SHAT from the factory.....but it was good enough for back in the day...and as is said even today..."Shat will run", and it does.
So,
if you are just planning on putting heads on an otherwise good running Engine....then GO FOR IT ...it is yours.

BUT, IMO...I don't think your Machinist is necessarily exaggerating ?
I Machine & Build Engines daily....never surprised me the crap I have seen over the years from the factory...but IT RAN FINE. 

[ws23rt]

I have a low miles 1969 383 short block, pistons 0.005 in the hole. my plan was to put a set of ported stealth heads on it and run the short block as is. I was talking with the local machine shop about the heads and the machinist says it is imperative that the block be line bored, decked and bored to true everything up. are mopar blocks that poorly machined from the factory that they are not to be trusted. Is this machinists doom and gloom stance on factory mopar iron warranted.

opinions please.

Yep...IMO...they were Machined like SHAT from the factory.....but it was good enough for back in the day...and as is said even today..."Shat will run", and it does.
So,
if you are just planning on putting heads on an otherwise good running Engine....then GO FOR IT ...it is yours.

BUT, IMO...I don't think your Machinist is necessarily exaggerating ?
I Machine & Build Engines daily....never surprised me the crap I have seen over the years from the factory...but IT RAN FINE. 

It is amazing what can run fine. I was talking to a service manager in a dodge shop (early seventies) and one of the mechanics came up to him with a cam shaft from a customers car. There was a section of the distributor drive gear teeth missing. It looked like about 25-30%. It was a factory flaw that got missed. The spiral of the mesh was enough that it worked without skipping. The car was in for unrelated problems.

[fy469rtse]

Did you do a compression test before you pulled it apart , lets not be too hard on mother mopar , it was the best machining that was available at the time, we are spoiled with today's technology,
When always choosing a block to begin with, the casting numbers the number following the dash is the number of blocks cast from that sand mould, they checked every third one for bore shift, so when ever I start a new engine I pick 1,3 6, after the dash line , once hey have been sonic tested for bore thickness, always been lucky this way,
What are the casting numbers on yours , get another opinion on what's needed,

[Cooter]

I beg to differ, there were top fuel engines as well as very powerful Street engines When these engines we're being produced by Chrysler.
blues engines what machines to the best of the day. Chryslerput out mass produced engines up more clearly pieced together from poor casting procedures. These were simply sent out the door with under/oversize parts instead of doing it correctly like todays engines.