You said you have an 01 z06 cam? That is different than a 02+zo6 cam that has a smaller base circle (not larger) the 01 z06 cam has the same base as any Ls1

 

the 02 cam is 550/550 the 01 is 525/525. thos springs are for 01 zo6 (blue about 2 bucks at the dealer good for that cam) The yellow ones are about 9.00 a peice and are good for well over .550. I would go with a bigger cam lift and a little more duration your gas mileage will not suffer that much. With all my mods I still get 18-19 on the e-way at 65-70 mph. my cam is 207/230 w lift over .600 w/ the 1.85 rockers. still idles stock. check out Lingenfelters LS1 cams I think They have one you would be very happy with springs and all for under 400.00

 

yellow springs have came way down,around $70 a set