300 HP out of a 318, is it possible with bolt ons?
From what I understand you need around .250-.300" of space between the wall/chamber and valve for there to be no valve shrouding. So Probably every small block has some valve shrouding, I imagine in almost all cases less is better so yes 340/360 will have an advantage over a 318 bore but by how much ? In all the years on here people go on about it but yet see anyone ever measure it. And generally most aren't using up all of the available power potential that any given heads offers anyways. But we do know a 318 has more than enough bore to satisfy most people power demands especially ones starting with a 318, I bet a 273 bore is capable of suppling more then the power that the average A Body owner wants. Does that make them the best choice, obviously no but an capable choice if one chooses for whatever reason.
Most of the valve doesn't come near the wall and where most the flow goes isn't near the wall either, not saying there's no effect but probably a lot less then most are assuming. I remember a flow bench comparison between a chevy 3.75" vs 4" bore and I'm pretty sure there was something like a 5-7 cfm difference on that one particular test. And the difference between 305 and 350 bore is .250" same as between 360 and 383 which I find funny cause most that say that the 318 .90-.130" less bore is a huge deal but gaining a .250-.375"+ with a 383/400/440 bore ain't worth the trouble lol
Again no one is saying a 318 is more capable than a 340/360 that there just more capable then a lot want to give them credit for, if the naysayers were more realistic with their naysaying we wouldn't have most of these 318 debates.
From what I understand you need around .250-.300" of space between the wall/chamber and valve for there to be no valve shrouding. So Probably every small block has some valve shrouding, I imagine in almost all cases less is better so yes 340/360 will have an advantage over a 318 bore but by how much ? In all the years on here people go on about it but yet see anyone ever measure it. And generally most aren't using up all of the available power potential that any given heads offers anyways. But we do know a 318 has more than enough bore to satisfy most people power demands especially ones starting with a 318, I bet a 273 bore is capable of suppling more then the power that the average A Body owner wants. Does that make them the best choice, obviously no but an capable choice if one chooses for whatever reason.
Most of the valve doesn't come near the wall and where most the flow goes isn't near the wall either, not saying there's no effect but probably a lot less then most are assuming. I remember a flow bench comparison between a chevy 3.75" vs 4" bore and I'm pretty sure there was something like a 5-7 cfm difference on that one particular test. And the difference between 305 and 350 bore is .250" same as between 360 and 383 which I find funny cause most that say that the 318 .90-.130" less bore is a huge deal but gaining a .250-.375"+ with a 383/400/440 bore ain't worth the trouble lol
Again no one is saying a 318 is more capable than a 340/360 that there just more capable then a lot want to give them credit for, if the naysayers were more realistic with their naysaying we wouldn't have most of these 318 debates.