DeltaT

iTrader: (5)

I have an opportunity to sell my current 1.6 Comp hi-tech roller rockers at a good price. Is the extra lift of going to a 1.65:1 rr, say .016" on each valve, worth spending like $150 to obtain?

The rr change would bring my net lift to about its max for my roller springs:

Intake - .593 instead of the current .575"

Exhaust - .602 instead of the current .584"

My heads are ported Edelbrock E-Tec 200's with the chamber opened up to match my bore, and the flowcharts do show an increase in flow on both the I&E up to .650". So the extra lift could be used by the heads, but how much difference could it make?

Or should I consider a spring change that would allow me to go to 1.7:1 rr's but would be more expensive? Net lift would end up around .610I/.618E, but may also need valveguide & seal mods. If I went that route I would consider going all the way to 1.8:1 rr's and mods.

Thanks,

Jim

ddnspider

iTrader: (26)

are your heads still increasing flow with the higher lift?ie do they flow quite a bit better at .600 instead of .550" lift?if theres a nice different it might be worth it whereas my heads start leveling off at .500 so itd just be more strain on my valvetrain.

black98ws6ta

iTrader: (77)

I just wanted to clarify that, are you running stock rockers now? I'm sure the car would pick up some but dont know of a way to predict power gains. Maybe the fact that your going to a better rocker thats more stable will help justify the cost.

stevieturbo

Dont know. But Ive just ordered some 1.75 Jesel SS rockers for my car, and getting rid of the 1.7 YT's.

That should take my lift from 0.581/0.591 to 0.598/0.608

Im hoping it will be worth it.

52172

iTrader: (2)

It will be worth it as long as the heads continue to flow more at the higher lift.

2001WS6Vert

I went from stock to 1.85 Comps mostly because I wanted to be able to adjust the valves. I could not feel any difference but I did not dyno before/after.

stevieturbo

But with the bigger rockers, it will have more lift everywhere whilst the valves are open, not just at max lift.

So generally there should be airflow gains throughout.

DeltaT

iTrader: (5)

No, 1.5:1 would be stock, but I started right out with 1.6's.

The heads show flow improvement all the way to .700" on the intake side, although it tapers off a bit after .650".

Super Chevy did a dyno of Danger Mouse with a procharger D1-SC, and they got a huge improvement just from switching from 1.5 to 1.6. I just want to maximize my current setup before I upgrade to a T-trim.

Everything in my motor can handle up to 7000rpm and probably a max of 650rwhp. The GMPP 4-bolt block has a short fill of HardBlok and everything is forged and balanced.

Thanks,

Jim

52172

iTrader: (2)

Your right so the power increase should be the full curve on the graph.