More info on NA cars and other camshafts available that won't throw shims and can be used for 100k+ miles without wearing out anything?We've been doing alot of head stuff and for turbo and NA folks using camshafts under 12.5mm of lift and for that matter stock unported intake manifolds, the 531/405 head is a waste of your time as it won't make more power, especially under the curve.
Seriously though, I need a package. This partial package obviously isn't working. The H cam would be good with this header(or none!) in a stock car.
The exhaust sides of the two heads are basically the same... We're talking about the differences in flow through the intake side. The 530 is able to keep up some good velocity for good cylinder filling/efficiency below 12.5mm of lift whereas the 531/405 heads have a large port that will not be as efficient/powerful at lower levels of lift. You can see better than stock 531/405 flow numbers with a professionally(Erland Cox, etc.) ported 530 head that still uses stock sized valves.Is that a bone stock 531?
What about a 531 with minor exhaust porting and 38mm valves?
Flow numbers of one component don't tell all. Hell, my car with a basically stock head would likely make almost the same power it does now after bigger valves and port work(2018 update: crappy port work and blending of the larger valves). I hope to be getting rid of the stock intake manifold soon to see if that limitation will go away and provide decent gains. Then I'll have to look at getting a larger exhaust manifold and larger cam, again. At that point though, decent power should be achieved.
That actually makes power and is somewhat efficient...I'd rather folks have a complete package of an engine designed to all work together
Last edited: