Hello, new to the forum and I've been searching around for an answer to my question and can't find one. I have a sbc 350 that was bored .040 over and the cylinders are wallowed out .003 I'm assuming from pistons rocking back and forth because they're 4.040 one way and 4.043 the other. What is my best option here? I don't want to bore it to .060 over because I don't think it has the wall thickness. Would I be ok to slap pistons in it and go? Do I need to hone it and get oversized rings? Planning for a 400-500hp range that will eventually be turbod. Thanks to all that answer
Acceptable cylinder tolerances
- Thread starter Kseries78
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- 350 383 cylinder wear stroker
You're probably already close to the limit of the bore.
For what you would pay to bore it and then replace pistons and rings... you would be better off buying a new 4-bolt crate 350 and reusing your heads (if they are better than stock).
It would still be a better starting point to build upon than a severely overboard block.
For what you would pay to bore it and then replace pistons and rings... you would be better off buying a new 4-bolt crate 350 and reusing your heads (if they are better than stock).
It would still be a better starting point to build upon than a severely overboard block.
Bandit723
Veteran Member
I have to agree with Twisted...Especially seeing that you have uneven cylinder wall wear i would expect there are other issues. Pistons will cost you a few bucks but rings and bearings are affordable. .060 over bore is pushing it you are going to spend some money to see if this block will allow for it. There are other costs to getting the engine right so a good crate motor does look good.
Maximum piston to wall clearance is 0.0055-0.0065 measured at the centerline of the wrist pin perpendicular to the pin. I wouldn't be afraid to take a good core .060 the vast majority of 350 blocks will go that far and be ok. In my real world experience it's the late 80's castings and the Mexican blocks that have issues going that far. We have a member with the screen name CNCblocks that is a walking encyclopedia on GM blocks you might contact him with your casting numbers and he'll shoot you straight on whether it's junk or good to go.
slayer021175666
Veteran Member
Welcome to the forum!
The block is a four bolt main and I want to build something for the knowledge not buy a crate motor. I understand it is more expensive but oh well The engine I build will be bored 30 to 40 thou over anyway I'm just a little weary to go 60 over and I'm wondering if I could hone it out to say .045 and put over sized rings in and I will try to contact CNCblocks thank you fatkid_racing
MyBoTy
Veteran Member
The difference between .040 over and .060 over is .010 on each cylinder wall. If that makes the difference, you're pickier than me. Have it torque plate honed to .060 and go.
Was the block measurements taken with a deck plate TQ'd on?? If it was done and honed with deck plates, it should be measured the same way, just saying.
