I have a 318 LA that I am putting Magnum heads onto (EQ, "318-b" ones, if it matters)
I am putting a stock, standard, 360 2 barrel cam in along with it. (extremely similar to a COMP 252, minus 0.015" of lift which I will gain back and a lil more with the Mag 1.6 rocker ratio) but the standard 360 cam was 1/2 the price of the COMP, though it did take me a bit more work to find one than it would have for the COMP version.

I know that instead of 0.410" lift with standard LA shaft rockers, (1.5 Rocker ratio) with the Magnum 1.6s I will have 0.437---or something like that--- will duration, overlap, etc increase the same amount as the lift will?

No. The duration, while yes it changes, but is very minimal in comparison to the lift.

Only the lift changes with the increased 1.6 fulcrum. The lifter still comes back to the base circle on the cam at the same point on the degree wheel & everything is the same ex when the lifter starts to rise the valve is opened 1.6 times that lift amt rather than 1.5 times that amt. EDIT yes .410" X 1.067 = (new lift of) .437"

when changing rocker ratios the area under the curve increases. seat timing remains the same, .050 duration may change 1 degree, .200 lobe lift duration increases 5-7 degrees with a 1.5 to 1.6 ratio change. to notice the effects of ratio change camshaft duration must be measured at the valve.

I stand corrected. I thought only the lift(amt) changed(when going from 1.5 to 1.6)

if you could graph it out you'd notice the change. seat timing is fixed but lift increases meaning the valve will travel more in the same length of time. it's interesting to mock up a block-crank-piston and measure different cams at the lobe and then put a head on and measure at the valve with different rockers. once you see the changes you take rocker ratio changing and the effects little more serious. another thing about measuring at the valve is one finds what the true ratio is, and one finds out that "rated" ratios are not accurate.

stock rockers being that far off is pure myth. you'll find that aftermarkets are more off than factory. i've checked a few stamped rockers and they were all on the money. there's a lot of heresay and people repeating what some clown on some website says. to find the truth do your own checking, then you'll know.

thanks again for the info; Mag heads are on new cam n lifters are in but I dropped a da#n pushrod thru the lifter valey right into the pan, so off it came; I'm just glad its on a truck as I didn't have to monkey with jacking up the engine from its mounts, etc; just means I won't have it finished up completely til tomorrow. (dinner break now)