318 to a 390 or 392 stroker?

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limelight72

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for the 390 it would be .030 and for the 392 it would be .040. It's a late 70's 318 so I'm kinda iffy about the .040. Do yall think it would be safe to go .040?
I know the early 318 you could easily do .040

Is it even worth the .040 to say it's a 392? Lol
 
only thing that will tell ya for sure if you can .040 is to have the block sonic tested at the machine shop....

humans can not see thru cast iron cylinder walls...especially over the internet
 
70aarcuda said:
only thing that will tell ya for sure if you can .040 is to have the block sonic tested at the machine shop....

humans can not see thru cast iron cylinder walls...especially over the internet
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Yes, I know that. I was wondering if the 318s themselves could handle .040 over. Not just mine.
 
In the 60's we'd go .060 over without thinking twice as you'd still run stock class legally..

Like the dude said Sonic Test
 
Again, I will get it sonic tested. All I wanted to know is if the 318's themselves were able to handle the .040. Thanks to the second answer. All I wanted to know. Some people just cant answer without being smart about it.
 
Oh c'mon man, don't get your knickers in a twist...lighten up-welcome to FABO.

Here's another answer-typically, yes...
 
'73red-duster said:
If I do mine, it will still be a 318. Don't believe me. It's stamped right on the side of the block.
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Ya I'm not going to be one of those guys who try to say it's not a 318. Best thing is 318's are so cheap, if this one goes bad i'll take the parts out and get another block.
 
Friend of mine has a 318/402, it is 90 thou over and still plenty thick enough. I sonic tested a few other 318s recently and they weren't going to be safe at 40 thou over so its the luck of draw really.
 
My grandpa who's an old racer that knows ALOT about mopars told me a while ago that when you bore out an engine, bore only what is needed to make the bores nice, if it only takes 30 over, bore it 30 over.
 
DartVadar said:
My grandpa who's an old racer that knows ALOT about mopars told me a while ago that when you bore out an engine, bore only what is needed to make the bores nice, if it only takes 30 over, bore it 30 over.
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Good advice. I'm only going to do it .030 over just to be safe after it gets tested anyway.
 
DartVadar said:
My grandpa who's an old racer that knows ALOT about mopars told me a while ago that when you bore out an engine, bore only what is needed to make the bores nice, if it only takes 30 over, bore it 30 over.
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x2. A thicker cylinder wall will make more power than a larger, but thinner one will. Iron does flex and the thinner it gets. the more it flexes, and the ring seal is negatively affected.
 
evil66 said:
Friend of mine has a 318/402, it is 90 thou over and still plenty thick enough. I sonic tested a few other 318s recently and they weren't going to be safe at 40 thou over so its the luck of draw really.
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* I have my 1968 318 and hope it sonic tests o.k. for my 402 stroker..
 
.030 or .040 is there really any difference here? If you "feel" safe at 30, 40 should be good too. We are talking about .005" a side, or the thickness of a sheet of printer paper. Not going to make a hill-o beans at this point. Now if you were talking about going .030 OR .130", then you really need to have it looked at by a sonic tester. But to say you will be safe at 30 and iffy at 40, thats BS. If its not safe at 40 it aint going to be safe at 30 or even std for that matter.

But Im all for the LEAST amount of over bore, if it cleans up at .010 and we have a piston/ring combo that fits that bore, then thats what it gets.
 
MRL Performance said:
.030 or .040 is there really any difference here? If you "feel" safe at 30, 40 should be good too. We are talking about .005" a side, or the thickness of a sheet of printer paper. Not going to make a hill-o beans at this point. Now if you were talking about going .030 OR .130", then you really need to have it looked at by a sonic tester. But to say you will be safe at 30 and iffy at 40, thats BS. If its not safe at 40 it aint going to be safe at 30 or even std for that matter.

But Im all for the LEAST amount of over bore, if it cleans up at .010 and we have a piston/ring combo that fits that bore, then thats what it gets.
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Which is why I'm gonna get it sonic tested. Just wanted to know if later model 318s were good with it.
 
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