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Old 12-02-2004, 10:40 PM
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Which rocker arms 1.5 or 1.6 ratio??SBC

I'm looking for the right rocker arms for my new heads(dart 180/64cc).Not sure if I should get 1.5 or 1.6 ratio?I'm also interested in roller tip rocker arms.Are the worth the extra money....will I see a hp increase?Some companies claim 15-30hp over non roller tip rocker arms.Is this true? Here is the info on my cam......Please help me decide which rocker arms..also what are good companies to look at?I was looking at crane and comp cams

Here's that info.....Camshaft- Part#3863151 Hydralic Flat tappet
Intake Lift-.383" Exhaust Lift-.401"

Intake Duration @ .050"- 194 Exhaust Duration @.050"- 202

Lobe Seperation-112

This cam Has a mechanical Fuel Pump Lobe. This is a low end Torque oriented camshaft.

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Old 12-02-2004, 10:45 PM
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Guaranteed the best choice rocker for you is a stamped 1.6 rollertip.
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Old 12-02-2004, 10:52 PM
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1.6 rockers are more efficient.

I hope those lift figures are cam lift and not valve lift.

Do not get roller tip rockers. The roller tip will not improve performance. If you are going to go roller, get some full roller rocker arms.

Full roller rockers reduce friction by using a roller bearing fulcrum point. The roller tip rockers still have the friction causing fulcrum ball.
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Old 12-02-2004, 11:16 PM
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The majority comes from the tip so roller tips do work.

LL, can you justify aluminum rocker cost on a cam with max lift of 400"?

under .480" lift and 5250 RPM aluminium rockers are overkill.
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Old 12-03-2004, 12:18 AM
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1.6 rockers would change your specs to .408/.428 lift,,,197/205 dur.,,,1.6 rockers work best on bigger engines.i have roller rockers and am not convinced that they are better than roller tip.however if you can go to ebay or somewhere and find the rollers for a good price i believe it is worth the effort.i don't rmember the name of the stoe at ebay right now but it was a racer store that had scorpion roller rockers for i think 129.00.i'm all for that.they looked like they were good piece's.your cam is so small that you'd do well to spend about 60-70 bucks and get a much bigger cam.you have to take your time in ebay stores or in new and used race parts in classifieds but the deals are out there.i've spent the big bucks at jegs for yrs.since they are so close to me and still will for some things but here lately i have been enjoying saving big money on ebay.if you go to 1.6 rockers you may want to get some new siffer valve springs.
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Old 12-03-2004, 06:40 AM
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this motor does not need 1.6 rockers. 1.5 stamped are fine for what you're using. Most roller tips dont even roll, they just slide across the valve just as a regular stamped part would do.

I could understand getting 1.6 if you're interested in gaining some top end, but it doesn't sound like you are. 1.6 are going to do nothing but hurt your bottom end which is what it sounds like you built the motor for in the first place-

K
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Old 12-03-2004, 07:39 AM
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With a cam this size the only place bottom could possibly even be hurt would be below 500 rpm...and when does your motor see that speed?
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Old 12-03-2004, 07:51 AM
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I disagree. When the cam company ground that cam they had 1.5 rockers in mind. The purpose of a smaller cam is to keep the intake velocity up and thus create torque by forcing airflow to mix at lower speeds by moving it through tighter spaces. The minute you open up one of those spaces, you risk losing torque off the bottom. So what happens if you have a carb that's too big? Airflow velocity suffers. Usually gain a couple of points on the high end and your low end and throttle response will suffer. What about an oversized intake port? Same deal. What about lifting the valve higher at lower RPM? Well, you've just decreased airflow velocity so guess what, you're going to lose some response and low end. Again, I could see how I woudl justify using a 1.6 on a motor thats in a lighter car that has a stall and a 280ish cam, but that is not the case here, and this isn't even a big cube smallblock to make that justification either.

K
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Old 12-03-2004, 07:56 AM
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I'm just looking for some bolt on horsepower,I'm not looking to pull the motor.(cam will happen later)BM
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Old 12-03-2004, 08:08 AM
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Hello Killer,
I degress...the 1.5 showed 90993 hp on my desktop dyno and the 1.6s said 338 hp....so I guess you showed me!
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Old 12-03-2004, 08:19 AM
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1.5 vs 1.6 rocker arms

There are a lot better ways to gain power than to go to a higher ratio rocker arm. If you were to look at a dyno sheet comparison of the two, you would only see gains of maybe 2-3 hp at all points throughout the power curve with the higher lift. Sounds like you have a stock cam in your engine.

Youre better off going with a good exhaust system. I am presuming you have a V-8, and a good set of duals, even with your stock exhaust manifolds would do you more good.

Going to the 1.6 rockers will only get you a gain of 7% increase in lift and no difference in duration. I once asked a few camgrinder companies about any change in duration, and they all told me that going to higher ratio rocker arms dont affect duration. I was curious about that myself, the reason for calling them.
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Old 12-03-2004, 08:19 AM
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Quote:
Originally posted by killerformula
this motor does not need 1.6 rockers. 1.5 stamped are fine for what you're using. Most roller tips dont even roll, they just slide across the valve just as a regular stamped part would do.

I could understand getting 1.6 if you're interested in gaining some top end, but it doesn't sound like you are. 1.6 are going to do nothing but hurt your bottom end which is what it sounds like you built the motor for in the first place-

K

Killer, I don't know what books you have been reading, but a roller tip does not slide, it rolls, why do you think they are called rollers? Of course You will not feel any hp increase. but every little bit helps. But normally you can feel and hear the difference with 1.6 rockers, very slight but it's there.

Troy
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Old 12-03-2004, 08:24 AM
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Max,
I already have a duel flowmaster 40 series(w h-pipe) on my car.And yes I did see a big differencewhen I installed it.I'm not just getting new rocker arms.They are for my new dart 180/64cc iron eagle heads.Trying to figure out the right rockers for these heads.bm
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Old 12-03-2004, 08:27 AM
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1.6 vs 1.5

You would be far better off to spend that $125 or so on a little bigger cam, and go with that.
What size engine, what trans, rear gear, and vehicle is this engine in?
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Old 12-03-2004, 08:30 AM
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I don't want to pull the motor.Read some of the posts on the thread.bm
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