matman11

iTrader: (4)

i'm looking to purchase either yella terra or harland sharpe rockers and called up thunderracing and they said the stock rockers are fine w/ my application... i was wondering what the typical hp difference is between stock and those two aftermarkets and if it's worth buying one of them or not? i'm running a forged 347 w/ trex cam and a 92mm intake... get back asap i would like to order them today if i decide to

Halloran

iTrader: (7)

From everything I've read and heard is that the stock rockers are the way to go. For the extra $500.00 in rockers you won't gain any noticeable performance increases...I think somewhere between 5-10 hp.

flynlow3

iTrader: (2)

Stocks are pretty damn good. The aftermarket pro is they are roller and adjustable. Their con= weight. Dollar for dollar our rockers on the LS motors are worth keeping.

SOMbitch

iTrader: (8)

I think the biggest advantage is that a better wipe pattern can be obtained. This is especially important if your heads have bronze guides. TFS recomends aftermarket with their heads for instance.

LS1C5Vette

iTrader: (11)

You will get better high rpm stability with roller rockers and gain 3-5 rwhp up top with them, I saw one guy on here pick up 9 whp from a set of YT UL only.

JScamaro

iTrader: (6)

Also rockers don't cost $500. You can get a set of Yella Terra rockers for $380 shipped.

I have these with my TFS heads since aftermarket rockers are recommended. I'll never have to worry about losing needle bearings like the stock rockers.

vettenuts

iTrader: (4)

Forget the hp, just check the wipe pattern with stock rockers and your T-Rex and you will be shopping for something easier to correct the geometry on. I couldn't get the geometry correct with stock rockers and a smaller cam and it is harder to correctly shim the rocker stand. As previously stated, bronze guides don't live well with a bad valve train geometry and high spring forces. The stocker rockers are excellent parts, but as you stray farther from the GM design (lift, spring forces, etc.) the setup becomes more critical and the stockers are more difficult to get right.

Bottom line, don't make the decision based on horsepower, there is more to it than that. Either way, Yella Terra or other aftermarket rocker or stock rocker, don't just bolt them in as you can't do that. Take the time to set them up correctly then measure for pushrod length, don't buy pushrods until the rest of the valve train is setup correctly, then measure for pushrod length.

Halloran

iTrader: (7)

You're right. I was looking at the Comp Pro Magnums and the SLP series rockers which are both over $500.00. You can get the Yella Terras and the Harland Sharps in the $300-$400 range. Still not worth it imo.

JRracing

iTrader: (35)

I just purchased a set of Yella Terra ultra lite 1.7 adjustable rockers and they are $500, the non adjustable ones are like $380. It is more of a high rpm stability issue than HP. And as stated, the wipe pattern is very critical to get correct so it does not wear out the valve guides and seals. And with better stability at high RPM's comes better power up top. It may only be a few HP, but every little bit helps on a race motor.