Jim, let me toss out my opinion on this. The double springs are not
necessary for this application. More important is seat pressure and making sure
you
don't get spring bind based on your higher lift cam and if you increased your
CR. There has been numerous incidences of tappets going bad on our cars for
years. You need to do all you can to make your set up more tappet friendly.
That is why I feel that keeping your seat pressure low is important. IMHO 65
pounds of seat pressure is more than sufficient. If all you are going to do is
normal street driving you can probably get away with less. At 65psi I can do
6000 rpm (+ a little bit) in autox conditions without floating the valves. At
7000 you are floating, I did this by mistake once last year:( so I know. If you
are building a road race motor and you want to run 7000 rpm then you probable
want the big springs. I checked my "high performance" dual springs when I had
my motor apart this spring and found they gave about 95 psi of seat pressure.
I removed the inner spring and it brought things back down to the 65 psi
range. I ran all summer and had no trouble. As always your opinions may vary
Good,
Marty Sukey
|