Only had too wait about 2 months and pay $600, but they're here. Anyone able to spot what's different about this set?

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Joshua

Josh, 1.6 on intake 1.5 on exhaust.

Richard

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Part of Tyrde-Browne Racing

T&D or RAS? Did they give you a thicker wall shaft, if from RAS?

Lou

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Home of Slant6-powered fun machines since 1988

Richard is correct. 1.6:1 intake and 1.5:1 exhaust.

These are from Rocker Arm Specialist. It looks like a stock shaft to me. I'll be sure not to over torque the mounting bolts.

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Joshua

Even if you torque it to stock specs you might "smash" the shaft. I had to un torque mine and use plenty of red thread locker.



Greg

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http://www.youtube.com/hyperpack

Dumb question but why the different ratio intake to exhaust?

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Wayne

Because it should make more power. The exhaust isn't nearly as sensitive to how far the valve is opened, but it is sensitive to when it is opened and closed. One reason being there is, relative to the intake, a lot of pressure to get the exhaust moving out of the cylinder. Also, the exhaust port on a slant flows a pretty high percentage of the intake port so the valve doesn't need to be open as long or as far.

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Joshua

[quote]One reason being there is, relative to the intake, a lot of pressure to get the exhaust moving out of the cylinder. Also, the exhaust port on a slant flows a pretty high percentage of the intake port so the valve doesn't need to be open as long or as far.[/quote]

“Armed with that bombshellâ€￾, I think I will back off the lash on my exhaust valves and see if my big cam likes it. Presently, intake @ 0.024â€￾, and exhaust @ 0.026â€￾.

J Clarkson

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Good day to all, how much power or % of power would be reasonable to expect from adding these to a built slant engine? Has anyone ever tested to see the actual gain?
Thanks Derek

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70 Duster 238'', four speed ,3:91's, 500 Elde, Hookers
68 Dart 4 dr 225, completely original

There have been some A-B tests. Slantzilla will be happy to tell you to keep your money at they weren't worth a 1/10th of a second on his car.

You can't just bolt high ratio rockers onto an optimized engine combination and expect a power improvement. If the cam/valve timing is already optimized then you can and probably will lose power. Slant six heads don't flow well at high valve lifts so if you're already opening the valves far enough it doesn't help to open them farther. What high ratio rockers are good at doing is getting the valve off the seat more quickly. You can therefore run a shorter duration cam with high ratio rockers and get the same power with a better idle. It's all about the combination not any one part. You're changing part of a system and you have to consider it as a system.

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Joshua

The main advantage I can see is reliability under sustained high RPM and high heat conditions. For a drag only car or mild/medium street car, I would spend my money elsewhere, specifically more head work.

Lou

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Home of Slant6-powered fun machines since 1988

Lou's right. I forgot to mention the #1 reason I bought these rockers is for strength in a high RPM race engine.

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Joshua

I use stockers for up to 40 min road course sessions, and they wear the tips down at the valve and need adjustment, even after 1-2 track weekends. Biggest problem on #1 cylinder, which is the hottest. Fortunately, they are almost free.

I bought a RAS setup at 1.6 ratio but have been too chicken/lazy to run it since others said the shaft would crush when you bolt it down.

Lou

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Home of Slant6-powered fun machines since 1988

Why is #1 the hottest?


Greg

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http://www.youtube.com/hyperpack

It is the last chamber in the head to be cooled but the first cylinder in the block to be cooled. The water pump pushes the water to the back of the block and then up into the head where it makes its way back to the front of the head (past #1 last) and out the thermostat.

Tom

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11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc