Im currently running harland sharp 1.5 rockers on my 360 with a racer brown [Email]254@50[/Email] 520 solid.Would it be worth the effort /money to swap the intakes with 1.6's?

thanx
justin

There is no power increase do to a ratio increase except for the reduction in mass being lifted. The reason people see power gains is because the cam is not optimized to the combination. If you are under cammed it will help you, but buying the right cam may be cheaper.

No

It depnds on your expextations, if your expecting the ratio change to pick your car up a bunch, more than .10, then you are probally not going to meet your expectations, I think. I have switch ratio in the past but I also switched heads so that is not a good comparision, hopefully some others with first hand experience will post there results

I once went 1.6 from 1.5 on an ultradyne 263/271 @ .050 .597/.620 108 LSA cam with no other changes and if I picked up .05 it was real hard to tell???
Did run my best ever that summer but by .04 or .05 and day to day things well you know!!! LOL!!!

it depends, if your heads flow A LOT more at 6.6% higher lift, and your intake/exhaust balance favors the exhaust, then you might see an improvement. it depends on a lot of things.

thanx everyone,I'll prob leave it alone

justin

If your combo can use more duration and more lift then yes, the higher ratio will increase the power. Typically the largest gains come on the intake side.

Over time I've worked up to 1.85 as the intake ratio on my EZ heads and the motor has really picked up the power.

My cam is 260 @ .050 / .630 lift and is too small for my combo, with this small roller I am close to the max hp for a stock 59* block but I make good torque with it and can keep my max rpm down @ 7k, I have been fence sitting on goin to 1.6s to gain a little more intake lift for my W5s which will flow more than I am currently lifting,How do you think the extra lift will effect torque vs hp? I am trying to keep the rpm down @ 7k

Craig, more lift will help yours. I was answering him considering what he has.

More lift won't affect the RPM range. More rocker ratio will add a small amount
of duration but, not enough to matter.

Thankx Vic, I was hoping to keep my max turns down and this small block is dieing for more air,I have a cam that's just about like yours but on a 107 not 109 but I dont want to use it in this block. if I can gain a 1/10 I will be knocking at the door of a track record I have been chaseing but not at the cost of popin this puppie

and the thing that most guys forget changing from 1:5 to 1:6 is pushrod clearances, you'll probably need to clearance the block and heads so they dont rub.meaning the motor has to come apart.

reduction in mass being lifted

????

Jeff you know what I'm talking about. With the same valve opening (say .600) the 1.6 rocker lobe will be .025 shorter. At 7000 rpm thats 175" per minute you don't have to lift the lifter and pushrod.

Ah, yes... with the lobe adjusted for the same lift, thanks.

Actually, there's a tiny mass loss at the short lever when you change up the ratio as well, but not very significant.

But the added lift pushes the valve spring down tighter adding spring pressure to the equation.

Valve train weight aside, what about the fact that exhaust pressures are in the 1000's of psi and you have about 14 psi atmospheric pressure equalizing into a cylinder on the intake stroke. It would seem using a 1.6 rocker on the intake would help fill the cylinders, especially on a short stroke engine.