Sonic Testing ( LA Blocks )

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SS Lancer

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Greetings - fixing to start checking my blocks sonic testing so hopefully I have one that will work for my needs , trying to take a 318 and bore it 90ths to make 4.00 bore .
I have heard from two creditable folks who say it can be done .
I have the following blocks
2- std bore 1974 blocks
1 - 20 over 1968 block
1- 20 over 1970 block
Traditionally the older the block the better but we will see
Going to check the 68 & 70 blocks since they are not standard hopefully both are suitable for 90over bore thanks for any input.

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Good luck, let us know. What would the cubes be on that combo?
Good luck, let us know. What would the cubes be on that combo?
( Im running a unique crank with 3.20 stroke and 6.200 small journal Chebby H Beam rods ) so with the 4.00 bore it should be 321 CI .
If I was using the stock 6.123 rods and 3.31 stroke and 4.00 bore it would 332 CI .

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I’d love to see your results becUse then you could easily turn down a 360 crank and use a standard bore 360 pistons

There’s even a outfit in Canada that takes them to 4.040 or 4.070 and builds 340s put them
 
Interesting, early 318 blocks 67-68, I HAVE personally seen bored to 4.040. I wouldn't do it though, there is more power in a STRAIGHT and STIFF wall than a thin one. I'm sure no one on this site will agree though, but I am correct.
 
I’d love to see your results becUse then you could easily turn down a 360 crank and use a standard bore 360 pistons

There’s even a outfit in Canada that takes them to 4.040 or 4.070 and builds 340s put them
WOW - 4.070 with OEM 318 block ?
 
yes, not sure of the longevity on that or what further prep they do, they made a short fill or more, but they obviously find it a better solution that going through or finding good 340 blocks. but as the poster above you mentioned you cant/shouldnt/dont want to do it if the walls are too thin so I dont know how common these "thick wall" 318s are
 
Interesting, early 318 blocks 67-68, I HAVE personally seen bored to 4.040. I wouldn't do it though, there is more power in a STRAIGHT and STIFF wall than a thin one. I'm sure no one on this site will agree though, but I am correct.
Ten 4 !
Im just hoping my 68 or 70 block can safely go to 4.00 bore.
 
yes, not sure of the longevity on that or what further prep they do, they made a short fill or more, but they obviously find it a better solution that going through or finding good 340 blocks. but as the poster above you mentioned you cant/shouldnt/dont want to do it if the walls are too thin so I dont know how common these "thick wall" 318s are
Im going to do a partial fill also on my block .
 
yes, not sure of the longevity on that or what further prep they do, they made a short fill or more, but they obviously find it a better solution that going through or finding good 340 blocks. but as the poster above you mentioned you cant/shouldnt/dont want to do it if the walls are too thin so I dont know how common these "thick wall" 318s are
Eventually even the unwanted 318 blocks will dry up just like the 340
And other jewels Chrysler made.
 
If you are going to sonic check blocks, do the 68 & 70
First.
I have read mixed reviews on 68, (either epically capable, to fairly thin on a .030" over bore) & have not read of failures regarding significant over bore of 70 SBM's.

Ryan Johnson of Shady Dell has a write up somewhere on the SBM's,, Muscle Motors and 440 Source on the BBM's.

My non-expert opinion/guess after reading is that the 70 is your best bet, with the 68 potentially being thicker.
Not sure how much sonic checking will run you, hopefully this saves you money.
 
If you are going to sonic check blocks, do the 68 & 70
First.
I have read mixed reviews on 68, (either epically capable, to fairly thin on a .030" over bore) & have not read of failures regarding significant over bore of 70 SBM's.

Ryan Johnson of Shady Dell has a write up somewhere on the SBM's,, Muscle Motors and 440 Source on the BBM's.

My non-expert opinion/guess after reading is that the 70 is your best bet, with the 68 potentially being thicker.
Not sure how much sonic checking will run you, hopefully this saves you money.
Thank you
For info dropped 68 block off this morning getting it burned and blasted so when its done will check it and the 1970 block
Both are currently 20 over so
I will use one of them and store my two 74 model blocks which are standard bore for the future .
 
Yup it can be done. But ........but ..........but.........all THAT for 3 cubes?
 
I sonic tested several 318 blocks cast from 69 to 74 when looking at building a 318/ 390 stroker. Most of them were that thin that i wouldnt have dared building anything other than a stocker and some had to be thrown away they were that thin in several spots. My best 318 block was worse than my worst 360 block that i had tested.
 
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