What are your thoughts on these...

http://www.jegs.com/i/Proform/778/66914/10002/-1

they seem to be a decent price.

 

Why not get the 1.6:1 ratio for $25 more?

http://www.jegs.com/i/Proform/778/66...oductId=746729

You'll need new valve covers too - roller rockers won't fit under stock covers if you still have stock or stock-height covers.

 

Roller rockers will fit under stock center bolt valve covers just fine, if thats what your using.

 

sure they wont fit??? i didnt want to shell out the extra cash for these...
http://www.jegs.com/i/Proform/778/141-130/10002/-1
but if your sure...

my concern with the 1.6:1 arms is idk if theyd be safe to use. you tell me.

comp cams xe262
z28 valve springs
heads havent been machined to accomidate excess valve lift
still have the press in 3/8 studs

 

dang... them tall ones are EXPENSIVE!!!!!

 

or maybe these new ones from comp cams, cheaper and free shipping
http://www.compperformancegroupstore...AlumRockerArms

 

Not a bad suggestion. But still leads back to my concern about the 1.6:1 ratio

 

The 1.6 ratio has NOTHING WHATSEOVER to do with the valve covers. THINK about it.... what changes, when the rocker ratio is changed? Does the push rod end move up farther? No.... so what DOES change? Right: the valve end moves down, toward the head, farther, thereby pushing the valve down farther. How could that POSSIBLY be interfered with by the VC??

Right: it can't. Not an issue. Fuhgetaboutit.

But that doesn't mean that you won't run into problems. Only, that the problems you will have, will be THE EXACT SAME regardless of which ratio you use.

Where you WILL run into problems, is the little tubie features for the bolts, fitting down between the rockers; and the top of the Poly-Locks hitting the underside of the VCs. Roller rockers have MUCH wider bodies, and therefore less room between adjacent cyls; and the Poly-Locks are VERY tall. Odds are, you'll need taller VCs, and they'll need something different about those little tubes.

 

My concern with the 1.6:1 rockers doesn't have to do with the valve covers it has to do with the overall valve lift and whether the valve springs can handle being compressed that much

I'm gonna try to dig up more info on the springs. I've got the cam specs but I don't remember how to calculate total valve lift

 

Well then, that depends on what cam you have, and what springs they are, and how they're set up.

 

-comp cams xe262 flat tappet
-z28 valve springs (not having the easiest time finding info on them)
-press in 3/8 studs
-heads havent been machined to accomidate large valve springs
-3 angle valve job (if that even means anything)

 

With that cam and that setup, there will be little gain from the higher ratio. Most of the improvement from changing rockers, will be just from getting the stock stamped sheet rubber ones out, and putting real metal ones in their place; and from getting rid of the ball fulcrums, which will lower the oil temps by around 5-10° and keep it from getting burnt and black near as fast.

 

cool... i just wanted to make sure no damage would be done with a higher ratio

 

I would certainly check maximum lift and coil bind of your heads and springs before I did the switch to 1.6 rockers. They will put you right at .500. I think either those comp rockers or the proform will fit the stock heads.

 

thats why ive been leaning toward the 1.5:1 ratio.

max valve lift is ur lobe lift times the ratio of the rocker arms right?

 

Yes. The valve lift value given in the cam specs is with a 1.5 rocker. They also give lobe lift for use in calculating lift with other rocker ratios. You may be fine with the higher ratio and you will get more power across the board. Just do some checking. To find max lift of the head, remove one valve spring, have the piston at TDC and use a holding fixture to prevent the valve dropping into the cylinder, then install a light spring to maintain pressure on the valve, with retainer and locks installed. Now, using a precision ruler or dial indicator, measure travel of the valve from closed to fully open.

The manufacturer should be able to give you coil bind on the springs. You can measure it yourself using a valve spring measuring tool. Maximum lift should be at least .020 less than coil bind to guard against spring breakage.