Camshaft Selection Information
128-(344.7/8/2.02*.91) is 108.5893
I’ve run it 3 times. And that’s too wide IMO.
I see it now. The eqn format is in non-standard form as far as algebraic order of operations. The eqn indicates that the 2.02" is multiplied by the 0.91 constant as a denominator itself (2.02*.91), not as 0.91 being multiplied by the resultant of (344.7/8)/2.02.
LSA=128-(((344.7/8)/2.02)*0.91) gives the correct order and the 108.5893 as you point out. I thought 104.... seemed tight when I first saw the formula on one of his you-tube videos earlier today and ran it on this combo. Looks like David is taking the individual cylinder block volume, dividing it by the intake valve size and then multiplying that result by the constant 0.91.
Appreciate you helping me get that straightened out. I haven't seen a video yet where David worked an example using the eqn or could have spotted it earlier. One of his straight line graphs shown in one video indicated the LSA or LCA as I think David used, showed would be around that 108deg mark. Also noticed David offered different starting angle depending on if it was a Ford or Chevy and SB or BB. Didn't see one for Mopar. He indicated the 128 formula was for a SBC with 10.5 SCR.
I'm not sure the combo would make the 400hp. That is just my goal. I had read a Motor Trend article rebuild of a stock 1970 340 (w/X Heads) and upgrading carb, intake, camshaft, valve springs and headers. Didn't these 340's have an advertised SCR of about 10.5:1? They used the Comp XE268H cam(110LSA), RPM AirGap intake, upgraded the valve springs, Edelbrock 800 AFB, 151/48 collector size headers. They didn't mention the tube dia but probably 1-5/8".
They said the combo cranked out 391.6 Hp@5700 rpm and 412 lb*ft of torque @3800 rpm on their dyno. I'm no expert by any means as this if my first Mopar build but I am willing to keep an open mind and learn.
Thanks again
