BobbyO01

I have a 2001 Z06 and I am trying to get some opinions for my next mod, of course I am looking for best bang for the buck like everyone else. I have PRC 2.5 heads, 233/239 cam, TSP longtubes with catless X-pipe, Fast 92 with TB, 25% underdrive crank pulley, RAM HD clutch, Tick MC, and all the supporting mods. Here is what I am thinking:

390 Gear
1.8 rocker arms (haven't done enough research on this yet)
100 shot (which I am sure i will need a new tune)
Maybe smaller rims with DR's
Coilovers (but wow they are expensive)
Brake upgrades (more go than slow)
I am sure there are other things I can't think of at the moment.

I have a friend who is a great mechanic and doesn't charge me for what he does unless its big, but he lets me use his lifts for free. I am considering maybe exterior mods or maybe the stereo but I hardly use it in the car, I love the engine sound. My car is not a daily driver but I don't want to lose any dependability at the same time.

Any thoughts are appreciated, thanks for the help.

NukeC5

What is the car going to be used for? Drag Racing? If so, drag tires on some smaller rims is the best possible upgrade, followed by gears. I wouldn't even mess with 1.8 rockers. They cause a lot of valve train stress. Once you have the grip to launch at full capacity, then you chase more power. Hit it with nitro or FI after that. Suspension upgrades only come once you find it hard to hook up again. Thats when you need coilovers etc. for fine tuning your launch. But as long as you're hooking up fine, I wouldnt worry about suspension yet.

If circle track/ road racing, the coilovers move to a high spot on the list of importance. As well as the brakes.

mrr23

How do 1.8 rockers cause more valve train stress? I wonder what gm has been thinking over the decades by going from 1.5 in the original sbc all the way to 1.8 in the ls7 motors?

NukeC5

When an entire engine is designed to run 1.8 ratio rockers it's fine. When it's not, it creates damaging valve train geometry. Besides, the desired lift and duration should be achieved by the cam. Adding 1.8 rockers simply says, I didn't select the right cam, now I'm trying to make it bigger the half *** way.

Bill Curlee

half *** way! YEP,, TRUE STATEMENT AND,,, YOU MAY END UP WITH PISTON TO VALVE clearance issues with that aftermarket cam.

If you want to do something with the rockers, up-grade to COMP CAMS Trunions for better reliability.

BC

mrr23

W
ell we can go round and round on this subject. I've done 1.8 rockers numerous times on my own cars on both stock and aftermarket cams with no damaging affects. If they are so bad at creating stress, then why are they offered by even the top manufacturers like comp cams?

And I drive my cars everyday. 1.7 and 1.8 rockers have been in big block motors since inception. Not to mention top fuel, pro stock, and nascar use upwards of 2.0 to ratios.

mrr23

So we shouldn't use ls7 lifters as an upgrade in the ls1 motors as they were designed for 1.8 rockers?

Adding 1.8 rockers increases lift and duration at the valve while reducing stress at the cam. You can use slower ramps speeds which reduces the chances of the lifter lofting off the cam lobe at higher rpms.

mrr23

maybe. Which is why he will need to talk to his cam manufacturer about that.

Trunion upgrades do nothing to prevent the rocker from twisting in the factory stands like mine did in my stock internal motor. They only prevent the needle bearings from blowing out.