63SplitWindow
Well-Known Member
What is the max bore size for a 360 LA block? Would that be the same for a 318 block?
Wow.....that's more than I thought could be done safely but understood......your mileage may varyThe 360 in my Dart is bored .070 over, but it is best to sonic test the block to make sure of how far over you can go.
I would say that you need to get any block sonic checked to be sure.What is the max bore size for a 360 LA block? Would that be the same for a 318 block?
What is the max bore size for a 360 LA block? Would that be the same for a 318 block?
I would like to point out(not trying to start a pissing match) that a 318 technically cant be bored that big. Its a different casting than a 360 although people will tell you because they look identical in appearance that the 273/318 blocks is the same as 340/360 it really isnt . same with the head castings. An astute student of small block Mopar will learn to go with a 360 or 5.9 magnum. It gives back the most dividend in power in terms of investment than a 318. Simply meaning for the same effort that you would put into a 5.2/ 318 you'll get more back from a 5.9/360What is the max bore size for a 360 LA block? Would that be the same for a 318 block?
My question was more about how big can I go safely with an LA 360 block. I picked up a block that was already machined and prepped for rebuild with a .040 bore.the answer to your question is that 99% of the time a 360 is going to have a bigger bore because it starts way bigger
318= 3.91 factory
360= 4 inch factory
huge difference
My question was more about how big can I go safely with an LA 360 block. I picked up a block that was already machined and prepped for rebuild with a .040 bore.
My question was more about how big can I go safely with an LA 360 block. I picked up a block that was already machined and prepped for rebuild with a .040 bore.
I took your question at face value. Part of it was….is the 360 bore more than a 318. I answered that pretty clearly.My question was more about how big can I go safely with an LA 360 block. I picked up a block that was already machined and prepped for rebuild with a .040 bore.
I have a .030 over 340 is that a 346? almost a 350 ! LOL! but seriously I agree. Best way I can describe how I see boring is go over just enough to clean up the cylinder. If you keep sharpening a pencil eventually you will have to throw it out and get a new one right? basically don't go over any more than needed save some for later..040" should be fine, but I always sonic-check a block these days.
I had a standard-bore 318 that wouldn't have safely withstood .020" halfway down #2 in the 9 o'clock position. Otherwise, it would've gone .060" easily. A few years ago, one of the Engine Masters Vintage class entries was a Poly 318 that used an LA block (he couldn't find a proper Poly) and the builder claimed .090" was rarely an issue on 318s through '76 or so. Would I do it? No. I agree with the others that have stated keep the walls as thick and rigid as possible. A couple of cubes will not make up for wall flex. The 340 for my Challenger is only .020" over because it was clean there.
If you're hanging around the kind of people that refer to their 350 and 400 Chevrolets as "355" and "406" just because it's been bored .030", find smarter friends (or more confident in their manhood). I've never heard a Mopar guy say he's got a "four-forty six" unless it was immediately followed by "pack". A .040"-over 360 is still a 360 to me.
I'm not sure why some guys get so bothered about people stating the actual cubic inches of an engine, after all that's what the factory did. It's not like they "named" a 340 or a 440, they just simply stated the actual cubic inches. With that logic all stroker engines are what the block started out as, and although I know a lot of guys (mostly street racers) that subscribe to that it doesn't go over over well in class racing or when trying to pick the correct camshaft lol. To the op I have built quite a few small blocks .060 over (with no sonic test) with no issues but the only way to know for sure where a block is at is to sonic test it.If you're hanging around the kind of people that refer to their 350 and 400 Chevrolets as "355" and "406" just because it's been bored .030", find smarter friends (or more confident in their manhood). I've never heard a Mopar guy say he's got a "four-forty six" unless it was immediately followed by "pack". A .040"-over 360 is still a 360 to me.
LOL! I had a guy tell me my J heads were "Just 360 heads..." because they had 1.88s in them, which I then quickly realized this "expert " I was chatting with was unaware that the J head could easliy be fitted with 2.02s and serve well as a "340 " head LOL!
Sonic check it! I had a 340 block that was paper thin, under .030 with a .030 overbore already done to it. Once it’s done, then you know! Plans can be made.What is the max bore size for a 360 LA block? Would that be the same for a 318 block?
I had originally written it in my post but must've deleted it at some point: Strokers are a different ball o' wax. That's a sea change in displacement, not five or six measly cubes.I'm not sure why some guys get so bothered about people stating the actual cubic inches of an engine, after all that's what the factory did. It's not like they "named" a 340 or a 440, they just simply stated the actual cubic inches. With that logic all stroker engines are what the block started out as, and although I know a lot of guys (mostly street racers) that subscribe to that it doesn't go over over well in class racing or when trying to pick the correct camshaft lol. To the op I have built quite a few small blocks .060 over (with no sonic test) with no issues but the only way to know for sure where a block is at is to sonic test it.