whats to use or is it overkill

[chevy6673]

std rockers or roller rocker arms .for a 400 hp bb thanks for your thoughts

 

[Rex S]

Roller rockers are "free" HP if you don't mind the expense

 

[TimAT]

Roller rockers are "free" HP if you don't mind the expense

erd:

I agree. But also look at long term durabililty. I'm running factory long slot rockers with the pivot balls that are grooved- also factory parts. ZL-1 factory cam and springs, and have never had a rocker problem. 7/16 pushrods too.

And for the difference in cost between the factory rockers and the rollers what can you do with the extra cash?

 

[JohnZ]

Roller rockers are "free" HP if you don't mind the expense

You'd need NASA-level instrumentation to measure the tiny power increase from the friction reduction; the stock rockers work just fine, and are utterly reliable.

 

[Hib Halverson]

You'd need NASA-level instrumentation to measure the tiny power increase from the friction reduction; the stock rockers work just fine, and are utterly reliable.

I'm not sure I'd agree with that if the context is an engine which regularly runs 6000 rpm or higher.

You can replace stock type stamped steel rockers with aluminum roller rockers and see a change in simple chassis dynamometer data above 6000 rpm. Beyoned 6000 is where the friction and oil temperature effects of production type rockers begin to cost power and torque. The higher the valve lift and the higher the rpm, the more the gain from roller rockers.

This is why one of the last developments in 1969 for Chevrolet's SCCA Trans-Am development was roller rocker arms for the 302.

It's also why an engine, like the old ZL1 discussed above, which could run to 6800-7000 rpm would probably gain some measureable power just from the switch to stamped steel rockers to aluminum roller rockers.

Conversely, add roller rockers to an engine which runs primarily below 6000 rpm, and the difference might be measurable but not much in a practical sense.

Lastly, I agree with "John Z" on the reliability/durability issue but I'll add that the roller rockers used on Gen 3s since 1997 are proving to be fairly reliable, too.

 

[Koop]

GM saw fit to equip new crate motors with roller rockers.

I'm just sayin...

 

[Vette79]

std rockers or roller rocker arms .for a 400 hp bb thanks for your thoughts

I'd go with BB full roller rockers and studs. Reduced friction and easier adjustments.

 

[JohnZ]

Conversely, add roller rockers to an engine which runs primarily below 6000 rpm, and the difference might be measurable but not much in a practical sense.

Precisely. The OP isn't talking about a "race motor" that's going to see 7000 rpm regularly; it's an ordinary production hydraulic-lifter big-block that will rarely see anything over 5500. In that context, little benefit will be noted.

 

[JohnZ]

I'd go with BB full roller rockers and studs. Reduced friction and easier adjustments.

All big-blocks already have screw-in studs. How often do you really adjust stock hydraulic lifters?

 

[chevy6673]

erd:

I agree. But also look at long term durabililty. I'm running factory long slot rockers with the pivot balls that are grooved- also factory parts. Zl-1 factory cam and springs, and have never had a rocker problem. 7/16 pushrods too.

And for the difference in cost between the factory rockers and the rollers what can you do with the extra cash?

looks like factory long slot wins thanks for the thoughts

 

[Crimson Thunder]

Just make sure you get a true 1.7 rocker ratio. I'd hate to lose some valve lift from an old defective rocker arm.

 

[TimAT]

I should have pointed out in my original reply- I keep the factory rocker nuts around too. I check/adjust the valves a couple times a year (solid lifters with .600 lift) and occasionally find that there's one I don't like the feel of and replace it.