The post I'm referring to is here: https://ls1tech.com/forums/showpost....7&postcount=28

Perhaps it was only because of the AFR heads?

 

To be honest Jim, any aftermarket rocker arm should be tested for proper valve swipe and then go from there. Including HS.

 

Viper, are you adding posts and then immediately deleting them to keep bumping this thread? LOL, cuz it's always back up at the top showing you just posted.

 

Nope, I think people are voting but not responding.

 

OH I didn't know a vote upped the thread, lol

 

i already asked one person on the board but does anyone have any before and after dyno numbers to prove a gain revving up to 6k rpm ? (i hate to run over 6) thanks! if less than 5 hp under 6k it wouldnt be worth the cost for me.

 

Have seen the HS's break several times !!

 

I know this is an old thread, but since I've owned the old style YT's and the Harlands I figured I'd chime in. After installing my TFS heads with the YT's (which I had for years) I took the car to the dyno in Chicago and found that my new heads netted nothing over the old Absolute Speed 241 castings. After a thread in the dyno section on what could be the problem, geometry problems were the main consensus. So after a very generous offer from Mike at TEA I purchased a set of used HS rockers from him. The switch was immediately apparent. The low RPM surging and bucking that I had attributed to the 112 LSA cam (I had been running a 114) was almost completely eliminated. The car felt much smoother in the upper RPM's. I haven't taken the car back to the dyno to see where the power is at, but if nothing else drivability is much improved.

On the flip side the Harlands are not as easy to install and don't feel as solid in construction. I may have been able to shim the YT's to get them to work on my setup, but in the end I'm happy with the Harlands. No headaches, just installed them and they worked as advertised.

 

I have read of a couple of people who had issues with the Yella Terra's on TFS heads, not sure why but they all switched to the HS and corrected their problems. Seems to be specific to these heads only though as everyone else seems to have had a lot of success with the YT's.

 

TFS heads? Is that Trickflow heads?

 

Yup. TFS = Trickflow

 

No issues here with my H.S rockers. I launch off a 2step anywhere from 6400-6800 rpm and shift at 7100 rpm

 

It sounds like incorrect lifter preload, and poor rocker swipe patten in being used as pros and cons compairing these rockers. Witch is a poor argument, I dont know if the YT and HS install at differnt specs. But If you read the YT instructions they come with rocker stand shims, and it walks you thu setting them up. I've also noticed 1st hand they alot sound quiter under the hood.

 

Based on everything I have read, very few take the time to check wipe or preload but rather prefer to "bolt in" and buy recommended pushrod lengths.

 

So let me understand this. There are two different Yella Terras on the market, an older version, which is heavier, and the new version which is lighter. I just want to make sure everyone is talking about the same thing and not comparing apples to oranges with the YT's. I'm guessing the newer, lighter ones are the preferred choice.

 

Yes, there are 2 types and the lighter new design is preferred.

 

will either of these fit/be a direct replacement of stock rockers on stock heads?

I might have thrown a needle bearing in my stock rockers and am currently looking for an upgrade...

 

my other question is... would I need adj. or non adj. ones? what's the difference besides the obvious word "adjustible"

 

bump...

 

Do the HS rockers have a one piece shaft cradle? Wouln't a single piece shaft cradle be more rigid than YT's four piece version?