Flow is not how you should pick a cylinder head. You need to know what you want from the engine, and then get the head csa where it should be. If you have a 2 heads, one flows 280 cfm at .500 and the other flows 300cfm at .500, Most times the higher flowing head will have a larger port/valve. If that's what the engine wants (HP, RPM) then it will make great power. If not, it will be a bag of $hit!
Brian
I agree. While it would be great to get 300 cfm of air through a head at .500 lift, it would be awesome if it were through a stock size (Ported) head. A big valve in my experience really doesnt do great things in the lower RPM and speed of the car. AKA, driving down the slow roads.
To much porting/ over sized valves on a street motor will cause a lag in the bottom. The heads I have are hogged out, with larger valves (cast iron). A friend that has been racing Mopars his whole life said they as good as very worked X-heads, I was going to put them on a 273 , he said no. Yes , I am off topic. However, if you have the right cam, gears, ect, a properly built mill, will pull hard, throughout the power band/ RPM range.
It's all in the combo. Considering the post starters first post and combo....
I have found a big valve can suck on the street in the wrong combo.
You should check out Dr DJ's air wolfs they flow 300 cfm @ .500 but there 220cc ports.
Seems to be a lot of port @ 220cc for a small engine.
The bigger valves and port work will do nothing........but make the 318 run better from top to bottom. I believe it would be difficult to get the ports too big in the Edelbrock head for the way your 318 is built, and that the head is probably too small for a really good running 408 stroker. But what the heck do I know?
In his current build state, I say probably. (An agreeing statement, to a degree, but) I do think the other side of this is the gear ratio and tire size he has chosen. I do not see it so well with the engine set up. While a bigger port may be good for this build, (IDK, haven't been there myself with a 318) I'm making a error (?) on the side of caution for this in favor of a recommendation of a port to large.
You make me LOL with this
But what the heck do I know?
So I want to know, have you done a 318 like above and if so, do you have anything for our viewing pleasure?
(Not challenging, just hoping so for more knowledge)
rumblefish, I know this is off topic. but are you having the same issue I'm having with the cursor disappearing out of the message box while you're trying to type?
RPM and engine displacement are relevant to each other directly.
Like it or not HP=TORQUE X RPM / 5252
therefore mathematically, all things being otherwise equal a 100ci motor would have to rev 2x as many RPM as a 200cu motor to pull the same air through the heads/carbs to make equal horsepower (at a much lower torque level)
Engines in their most basic form are an air pump. you have displace 20% less air per revolution you have a choice of performing 20% more revolutions in the same time period. or making 20% less horsepower.
re: driveline
Perhaps I could gain a tenth or two from changing my gearing and tires however it would completely remove the car's sleeper appeal.
I fail to see how increasing the average port flow in all used lift ranges by circa 30% could NOT cause a gain in net useable RPM and HP especially with a 114LSA cam.
I was on my i-phone, it worked fine. I'm home today (FREAKIN YEA!!!!) no problem. I get the wife to fix such things. I take care of 90% of everything else. ;)
Frosty, I think your reading this to black and white and not as a whole picture and on top of it, while you told me like it or not, well, again, I think that while formulas are great and experienced been there done that builds from our builders and members are tops, even more so when they have done near exact combos, I have found these formulas to not always work or work as intended.
While some things work out on paper, in reality, they can fail to do so in the real world working environment. And will do so.
It remind's me of a time when I was arguing that all HP and Tq. points do not always cross at 5252 or what ever the number was. 10 people said I was wrong and dumb. It took some time to prove them wrong, but by then.............
The 114 thing.....112 is pretty good as well. Crane cams does this a lot. Though the theory is sound in your head, the cam might not be cut in that manor. Check with the grinder before you purchase. Just let them know your looking for a super smooth idle.
Also, I forgot, the 1.6 rocker is a great idea in my mind. Though the head should be able to handle the lift. It is rare, but sometimes a lift rate to great happens.
All in all, I look forward to this and it's completion and testing and/or in car haulin ***.