i'm buying a zz4 to go with my mostly stock TPI. i know i will have to change the springs, should i change my rockers? what is ment by 1.6? what are some good "cost Vs prefomance" rockers?

 

SDPC recomended me to get SD1007 . They are 1.25 diameter and good to .570 lift . Send them an email ....because they sell that cam .....so its a good place to ask

 

i can get these for dirt cheap are they worth putting on with my zz4 cam?

http://www.paceparts.com/index.asp?P...D&ProdID=22756

 

There is a TON of info on ZZ4 cam swap, lots of it by me! Click the search button.

...in the meantime, yep, you'll need new springs.

As for the rockers, those that you've linked seem to be good old OE stock replacements. No need to buy 'em if you've already got some.

I wouldn't get 1.6s. Most of what I've read on the subject shows that "most" people that see a gain when switching from OE stamped rockers to 1.6 rockers see a performance increase due to the 1.6s being better made and thusly they don't flex. The slight lift ratio increase from 1.5 to 1.6 typically isn't what's causing the increase. What you CAN look into is a good set of 1.5 roller rockers.

For the record, I'm not saying that 1.6s can't help, but unless you're specifically in need of 1.6s, then typically it won't be a noticeable difference.

 

Just some food for thought ....


I pulled this out of a book called "How to build and modify Chevy smallblock v-8 camshafts & valvetrains" by David Visard


"On an air starved smallblock Chevy with a relitively short cam, high lift rockers can represent an easy way to substantially increase top end horsepower". On their test engine they swapped from stock to a magnum 1.6 and they gained 16 hp on the top end.
"On bigger engines we've seen gains as high as 22hp by makeing the change from a stock GM rocker to a 1.6 Competition Cams Magnum rocker"

SO .... what I get from that is ( could be off LOL ) if you have a cam that isn't quite optimal ....and it's on the small side .....you will see a gain by stepping up the ratio. That being said , the ZZ4 has a healthy exhaust and probably will not benifit from haveing a 1.6 rocker put on the exhaust. It could even hinder performance . But a single pattern cam ...on the short side would benifit.

Yup the search button is a wicked help too . just type in ZZ4 ....it'll take ya years tp read it all ....but there is a bunch of stuff.

 

It is difficult to know what 1.6 ratio rockers will do to engine operations without knowing your engine's camshaft specifications and other aspects of your engine. Basically what 1.6 ratio rockers will do will open your valves faster and higher to permit improved breathing. Stock rockers are 1.5 ratio. To increase to 1.6 ratio may require head work and rocker stud work depending on your current set up. If you are going to buy 1.6 ratio rockers spend a little more and get roller rockers both at the tip, but more importantly at the fulcrum. Then you want to probably consider self aligning rockers. I considered 1.6 ratio roller rockers, which with my cam would raise gross valve lift from about .48” to .51”. I discussed it with my mechanic who indicated it would be too much for my set up and for my use. Furthermore, it would produce a rough idle, which I did not want. Crane and Comp Cams are the leaders in this field. Discuss your proposal with your mechanic.

 

D's89IROCZ:

As you said, they switched from stock to 1.6 rockers. It's possible that a quality set of aftermarket 1.5 rockers could have produced similar results since they're not flexing. I've read that stamped OEs can flex as much as 1 and a half tenths. But don't get me wrong, maybe the 1.6 really did help in that situation. Given a mild cam, I can certainly see how it would help.

A mechanic friend said this when I asked him about using some 1.6 rockers.

"a good air filter is always a safe bet. Headers are always a safe bet. 1.6 rockers may help, but they not always a good idea. You don't use 'em cause ya got some extra lying around the garage"

...or something like that

 

Well, looking at comp cams site, and their magnum rockers, they are roller tipped.

As was stated, some high quality same design 1.5's need to be considered back to back with the 1.6's.

Obviously more lift IS going to make a difference, but there are so many variables it's going to be hard to say how much of a difference. However, reducing friction is always going to help, and running "stiffer" rocker arms in this case is likely going to help too, if the stock ones "compared" are indeed not as "stiff".

I don't think it would be such a big deal if the book didn't for some reason make so sure to point out that they went from a stock rocker to a comp cams magnum arm both times they mentioned it. If it were just a function of 1.6 vs. 1.5, you'd *think* brand wouldn't be important, nor would they have compared a roller tip against a non-roller tip.

Not berating the book or anything, just not an apples to apples comparison.

 

...and don't take anything I said the wrong way either. 1.6 rockers can be an awesome upgrade. It's just that recently I've noticed people starting to casually throw around 1.6 rockers as an upgrade that will help anyone and everyone.

My take on any upgrade I do to my car is that I need to be able to tell you why it works on my car. Because my friend said it would work is not good enough for me, even if maybe he's right. 1.6 rockers are similar. Bigger can be better, but it isn't ALWAYS better. If you're not sure, better stick with what you know.

...or ask!