Small block combo suggestions

Yeah I got some pretty disappointing numbers too out of the calculator. After double-checking my work and getting the same numbers, I began hacking off duration, by the time the numbers were coming into line, the net cam duration was getting so small, I knew I was in trouble, so that's when I posted #92 my calculator quit working. I can make the calculator work @ -5000 ft altitude. Not a typo;-5000
It's funny tho, cuz it still works pretty good on my combo. It's a little shy (within 2%,or so on my gauge,lol),but I just figured my tester was a little off; that can happen after a few years.
So my obvious conclusion was Marco ain't telling us everything, or Marco really knows his stuff, and, I'm really glad I don't share track time with him,lol!

I think that Wallace calculator doesn't work with mechanical cams. That 249-4 cam specs out at 306* at .015 valve lift. And it specs out at 260* at .050. Where the valve actually closes is anybody's guess.
However, we can guess! We see that the cam takes 46* to go from .015 to .050, which is a constant rate of 46/.035= .00076 " per degree. I suppose one could extrapolate backwards .015/.00076 and get 19.73*. These degrees would need to be added to the 306, and then those degrees used up by the lash would need to be subtracted. Doing all that, I get; 306+19.73-28.95=298* as the actual seat to seat. Yeah I know, that's a best mathematical guess, and overlooks all kinds of important things. but Marco (I think it was Marco), gave us a clue a while back; He said something along the lines of, the valve lash could eat up 12* of duration, from the seat to seat. But we can only imagine the seat to seat of this cam.
Elsewhere I seem to remember that the rule of thumb when ordering a mechanical cam was to order the next size bigger cam as compared to a hydraulic. Well backtracking from the 306mechanical, the next smaller hydro cam might be a 298.
Surprise,surprise, surprise!
In this case at least, the numbers want to agree. So if we use a 298* as the theoretical seat to seat, then, in at 107, we get an intake opening angle of; 298/2-107 =42BT, and then;
180-(42 +360 -298)=76*AB, the ICA.
And with that 76* number, we can hit the Wallace, which spits out a pretty good number; 8.25Dcr/166psi in a 30over 360 @sealevel. We know this works with iron heads. We also know that 11.5Scr can be made to work with the best gas and careful manipulation of the timing,fueling,and loading.
But like I said, the only way I could get the Wallace to spit out 195psi was to input -5000 ft altitude.lol
And the 298* seat to seat cannot possibly be correct, it is pure speculation on my part. I just love math......