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340 Block Sonic Results ---- What Would You Do?

Posted By: ScottSmith_Harms

340 Block Sonic Results ---- What Would You Do? - 02/26/09 02:38 AM

Check out this sonic test on a .040 over 1970 340 block. It could be run without further boring, no ridge or problems, maybe a dingle ball clean up and a finish hone. One cylinder is overly thin, the rest are ok but marginal IMO. Block magged free of cracks and has no problems otherwise.

Attached picture 5053390-Sonic1970340.jpg
Posted By: emarine01

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 02:49 AM

What stroke are going with , if your going 4" I would do a 1/2 hard fill, Looks like thin spot is on thrust side with stroker crank rod ratio wont favor a thin block , stock stroke has much less side load
Posted By: MR_P_BODY

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 02:54 AM

What do you plan on doing with this block.... you
could sleeve #1.... others are marginal on the thrust
and non thrust.... thin in the fore and aft
Posted By: ScottSmith_Harms

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 03:02 AM

No plans yet, just looking into my options. Not the best block I've seen but it's an original 1970 casting 340 with no other problems so I figure it's worth saving. One sleeve or all 8 (although pricey) would likely be the direction for me.
Posted By: Chuck@Best_Machine

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 03:04 AM

I think #1 already has a sleeve. 4" id .125 wall, - .080 for over bore or .040 per side = .080 sleeve thickness
Posted By: ScottSmith_Harms

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 03:27 AM

No, no sleeves yet Chuck, so says the local machine shop anyway, I'll be sure to have them double check. It's been tanked, magged, and sonic checked so far. I left 4 blocks down there for the same treatment to see what I've got, this is the first one I have a report on.
Posted By: DemonDust

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 03:38 AM

Quote:

No, no sleeves yet Chuck, so says the local machine shop anyway, I'll be sure to have them double check. It's been tanked, magged, and sonic checked so far. I left 4 blocks down there for the same treatment to see what I've got, this is the first one I have a report on.



Wow!!! You're gonna have $4-500 just in testing
Posted By: ScottSmith_Harms

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 03:50 AM

Quote:

Wow!!! You're gonna have $4-500 just in testing



And people wonder why a good, magged, good sonic checked bare 340 (or other) block costs so much, and why an untested greasey freshly torn down block that is "seemingly" a great core isn't worth much until it's been checked, your basic catch 22.

Now you know.
Posted By: MR_P_BODY

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 03:58 AM

Quote:

Quote:

Wow!!! You're gonna have $4-500 just in testing



And people wonder why a good, magged, good sonic checked bare 340 (or other) block costs so much, and why an untested greasey freshly torn down block that is "seemingly" a great core isn't worth much until it's been checked, your basic catch 22.

Now you know.



Yeah it cost to get them checked... fortunately I
have 3 good 340 blocks plus my R3
Posted By: DemonDust

Re: 340 Block Sonic Results ---- What Would You Do? - 02/26/09 04:04 AM

Quote:

Quote:

Wow!!! You're gonna have $4-500 just in testing



And people wonder why a good, magged, good sonic checked bare 340 (or other) block costs so much, and why an untested greasey freshly torn down block that is "seemingly" a great core isn't worth much until it's been checked, your basic catch 22.

Now you know.



I know all too well how that goes. I had an R3 block that had the same issues. It was brand new and couldn't handle a 4.100 bore safely. I was pretty upset to say the least. Everyone told me It's a R3 block don't worry about it. Had it checked, it was junk to me
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