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383 with a .060 over bored block?

14K views 24 replies 12 participants last post by  Baddbob 
#1 ·
I recently dissambled my sbc 350 that I had planned to build a 383 stroker out of. It was already bored over .030. There are slight grooves in a couple of the cylinders, Im being told i will need to bore it out to .060 over in order to use the block. I plan on putting quite a bit of cash into this build, and dont want to waste my money on a time bomb. If I end up using this block would it be reliable? Will it be able to stand up to 400-500hp? Or should i just find myself another block? Im a first time engine builder and i want to do it right the first time. I plan on driving the car 2-3 times a week, and the occasional dragstrip on the weekend. Any comments , thoughts, or experiences would be greatly appreciated.
 
#3 ·
you can just as easily break a std bore block... it's not the bore it's the components and how they work together and your care/use of the engine which will determine how long it'll last... don't worry about the 350 going .060 over... if you are concerned, have it sonic checked. that will tell thickness of bores etc... most cases though a 350 is OK for the .060 over bore...

good luck with the build. ;)
 
#5 ·
Is anybody running a .060 block? I plan on going the aluminum head and roller cam and lifters route. Once i get my car together, I plan to drive it like I stole it.:D With that being said i want it to be reliable at the same time. Im not trying to throw money down the drain.


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#23 ·
I pretty much had the same build, my last motor was a 388, 340 block .060 over with 3.75 stroke. It ran great, and held up well. As far as hp numbers I do not know what they were. But the come was sportsman II heads ported by dr j . Lunati voodoo solid flat rapper cam(257/265@ .050 560/580 on 108). Had a plenum ported hurricane intake, flat top piston etc. Well cam broke in 3 places. Motor was destroyed. I would do it all over again with better parts to make a long story short. So you should be fine
 
#9 ·
From what I see the later blocks maybe better because of technology gains, I have about 25 blocks where one cylinder has failed making the block junk for a performance build.

Going by core shift is a poor indicator from what I have seen.



I don't give ill advice or look into the crystal ball I sonic test each block. I move alot of blocks in a years time not many OEM's since the Dart SHP block. When I do have OEM block guys do want them sonic tested.

I wish I could base all my info on just one block:no:
 
#16 ·
Well going off of what CNC blocks is saying . Its probably better to be safe then sorry. But, if i go and buy another block with a std bore. Will i have to get it sonic test also at .030 over? Thanks for all the info.

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#17 ·
Overbore

I would agree with CNC I had my 327 362 block sonic checked before I even
thaught of machine work. all blocks are different the biggest issue is casting
shift. cylinders walls can differ in thickness do to casting process some blocks
may only take the 30 overbore and some make take 60 overbore as long you
have it checked out and you have good thickness on the thrust of all of the
cylinders. I personally do not run my set up on the, track you can buy on those
fancy dart blocks to beat on I think there are plenty of standard bore 350
blocks out there for a decent price. make sure you buy top end enternal
parts for your build. I spent $6000.00 on top notch parts and machine work
it is rare block and plan on keeping it that way
 
#24 ·
350 cylinder walls are plenty thick to handle .060 over
I have alot of blocks that are not good for .030 over that have no core shift
I have a real mild .060" over 350 that runs well, but also runs hotter than my 600 h.p. 400.

I had a .030" over 350 block that looked great as far as core shift went, but it had a spot in one cylinder that was about .035" thick, and poured water into that cylinder; at first glance it looked OK, but a little stained area in the bore was thin enough to stick a screwdriver through! We sleeved that hole because it was a low buck build with a Chinese crank and KB hyper pistons, but it still ran 10.20's at 131 in a 71 Nova.
 
#25 ·
A 350 bored .060 will run hot, A friend of mine bought a P.A.W. kit we assembled and it came with a .060 over block. Even with a 4 core radiator we had trouble keeping it cool in his 69 Nova but it ran good! 350 4 bolts are easy to find, I would do a .030 and that way you've got room for a .040 freshen up down the road.
 
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