Talking about solid lifter cams
Here is why I said that ; The solids have faster rate clearance ramps. This allows you to install one size bigger cam, without the cylinder pressure loss, usually associated with that amount of.050 duration
Another way to look at it is;with the same advertised,you can have the next larger sized .050
Here is an example, purely hypothetical;
a 262/268/110 cam, might have, as a FTH ,216/[email protected]. But same cam as a solid, might have 224/229.. That's a difference of 8/7, and one cam size is generally considered to be 7*
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Now from the other side, if you wanted a 216/222 cam, a FTH might be 262/268. But the solid might be 255/261, again 1 size difference.
To get a sense of that 262 vs 255, let's install these two, in the same 273 with no other changes, again at split-overlap, and lets make them 110LSAs. And I'm just gonna capture the important numbers from the Wallace Calculator, as; Scr/Dcr/Psi/VP.
>So with the FTH, I get;
8.0/6.62/125/82 This would be very weak.But with more Scr, I get
9.6/7.90/157/104 And still more
9.9/8.14/163/108 Here the pressure is maxed out for 95Ron, and you might have to run 98 for WOT work. So this is as good as it gets with a FTH.
> Next ,the solid; I get;
8.0/6.79/129/88 Again , weak, but better than with the FTH
9.6/8.11/163/111 About as good as it gets
9.9/8.36/169/115 Too much pressure now,for available fuel!
So now look at the Scrs, where the pressure is maxed out at 163psi. Notice the numbers are 9.9 for the FTH and 9.6 for the Solid.
If your 273 came in at 9.6Scr, and you installed the FTH, you would be sacrificing 6psi and more importantly 111/104= a loss of 6.7% in VP, and that's a heavy loss for a 273.
But if your Scr came in at 9.9 you couldn't even run an
equivalent-at-.050 solid, because the pressure would be too high.
