In my quest for used 1.9 rockers I came upon these on 3800pro for sale, 1.6 yella terra rockers with pushrods and bolts. How do they compare to 1.9 modified rockers as far as performance gains? Will I need springs or will they work with factory heads and cam? I've had no luck finding used 1.9 rockers and if these will work then I may get them. Thank you for any input

 

My guess is that they won't do much for knock or compression, but will resist valve float and allow you to shift at higher RPM. I think those are meant for a cam job, but I'm no expert...

 

I just found out there the stock ratio so will be no use to me so I'll continue my search for a used set of 1.9 modified. Its the last piece of the puzzle before dropping down to a 3.4 pully. Thank you

 

With your mod list you'll likely be knock-free without the rockers. But you should always scan. We're almost the same equipment so I'd like to see your quater mile time with and without the rockers

 

Ive got 2-3 degrees kr at times, usually at wot just before it shifts, so i dont want to take it down the track til i get that taken care of. Hopefully the rockers will take care of that. I have an aero force scan gauge so i monitor kr all the time.

Im assuming 1.7 yt rockers arent much of an improvement over stock? Another guy is selling a used set of them, but for almost the price of new zzp 1.9 modified rockers, so id probably be better of getting the 1.9's, especially since i only have enough saved for a used set of 1.9s

 

Those rockers are kind of more for people with a cam

 

Yes, 1.7 rockers are for people who have a cam. Don't use the 1.9 rockers if you're planning on installing a different cam in your engine. With these engines you either put a different cam in or you do rockers. Rockers are much easier to install but a cam will give you much better gains.

 

I plan on stopping once i can run a 3.4 pully with no kr so no cam for me. My goal is 300ish crank hp so thr 1.9 rockers and the pully are all i have left If it comes down to it and i dont find any used before the end of the year i may have to break down and save up for a new set.

Thank you for the information

 

Are you running colder plugs? With 104's and your mod list (more or less) I was able to advance the timing and be knock free with a 3.4 pulley. The only difference is that I have a custom street tune instead of zzp's pcm. No rockers yet

 

I agree, the 1.6's would be a little better than stock- less deflection in the rocker, but we're talking a super small difference. I'd be looking for 1.9 modded stock rockers or 1.8 or 1.9 aftermarket rockers. It would be a waste of time to do anything less IMO since you aren't going cammed.