Just installed the Century Spring and this is without a doubt, the best thing I have done to the car thus far! The clutch now reminds me a lot of the clutch I had in my 66 327 Corvette and 66 GT-350, with maybe a little less effort. I had NEVER stalled a manual transmission car until I got the Z. Now, I will not stall it again...
The increase in pedal effort is negligible, but the disengagement of the clutch is sooo much easier and smoother now. Good trade off IMO.
On another note, I purchased 4 springs, so I may have 2 (or 3) that I will send to someone who needs one for $15+shipping. Shoot me a PM
[QUOTE=bluenoser;1257678]Ok there's good news and bad news. The Fastenal spring I mentioned earlier doesn't work. The inside diameter of the spring doesn't fit correctly over the assembly. I ordered the day after I measured it and I guess I wasn't paying close enough attention when I placed the order.
The good news is that I found another spring after I realized the error that definitely does work. P/N 72577 at Century Spring is the winner
72577 - COMPRESSION SPRING - Part Characteristics | Century Spring Corp. The spring rate is roughly 20% of the stock spring and it feels very similar to running without the spring installed. The bad news is that you need to order 4 of them to meet their minimum order quantity.