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Roller rockers/stock valve covers

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ghinmi View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ghinmi Quote  Post ReplyReply Direct Link To This Post Posted: Oct/24/2013 at 10:53pm
You might get 2-3 hp, not 20-30.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote A0M797X112187 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/25/2013 at 6:58am
My understanding has always been that biggest improvement that using roller rockers does is help decrease oil temperatures and of course they are stronger than factory rockers. HP increase is nominal and is usually caused more by having accurate ratios because factory rockers are usually less than a true 1.6:1

Edited by A0M797X112187 - Oct/25/2013 at 7:44am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote badamx Quote  Post ReplyReply Direct Link To This Post Posted: Oct/25/2013 at 10:30am
I thought my buddy's claim of 20-30 hp jump was a little shall I say "optomistic"? I am sure with a more agressive cam and other valve train components combined the cumulative hp bump would be better.

The 390 has low miles and is set up the way it was the day it was born which I found very adequate over the last 5 years of driving her.

Are rollers alone worth the expense and trouble? Or would it be suggested I warm things over a little to make the car more lively?

Like I said my friend is a drag racer so it is his natural inclnation to seek more power. The car is one of 181 as it sets with the Go-Pack 390 4speed and red leather interior. I hate to corrupt it.

I have a 63 Falcon that I am making into a drag car so I can exercise my modification demons with that. Any thoughts?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amx39068 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/25/2013 at 11:23am
The 3-5 HP is from reduction in friction movement.  Some additional power however is gained from more precise valve tip to rocker relationship and valve movement but where it really shines is in combination with other modifications like better valve springs, a bigger cam and other modifications that work well together and produce significant additional power which will be otherwise somewhat diminished without the added benefits of the roller rocker. 

Think of it like getting a bigger carb or a performance intake each without the other.  There are diminished benefits for each alone but when you add them together the compounded benefit is multiplied beyond the sum of the individual parts.

For a mild build I use roller tip rockers on adjustable studs.  They are less than half the cost with much of the same benefits as full rollers and work fine with all your other stock valve train components.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 348AMX Quote  Post ReplyReply Direct Link To This Post Posted: Oct/25/2013 at 12:50pm
The rocker ratio also plays a larger roll in those advertised horsepower increases so common in aftermarket aluminum roller rocker marketing.

Most V8's came with a 1.5 or 1.6 ratio rockers stock, and swapping a 1.6 or 1.7 ratio rocker will net greater valve openning so there can be examples of engines that will get 20+ horsepower from higher ratio aluminum roller rockers over stock rockers. In engines that can benefit from the higher valve "lift" when the cam installed isnt optimized are where those advertised gains really come from.

The reduction in parasitic frictional losses dont really add to horsepower increases in a noticeable way at all especially if a flat tappet cam is still used. The camshaft lobe to lifter face contact is the greatest friction load in flat tappet engines.

You can gain 3 Horsepower from using different viscosity oil in some cases. So selecting full roller rockers soley for horsepower gains isnt practical.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Posted: Sep/26/2018 at 12:22am
Hey guys, my first post here on theAMCForum. 

Reviving an old dead thread for some similiar help. I am building a 401 for my Jeep. I am looking to add 1.7 roller rockers but want to keep my stock valve covers. I see several of you guys have posted that you have roller rockers under stock covers but are they 1.6 or 1.7? Anyone know if 1.7's will fit? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Sep/26/2018 at 12:35am
1.7 Harland Sharp works fine for me under the stock covers.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mixed up Quote  Post ReplyReply Direct Link To This Post Posted: Sep/26/2018 at 1:45am
I had Harlem sharp in my 290 with a 540 lift cam and edelbrock aluminum valve covers no problem but an more than that there might be issues
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Sep/26/2018 at 2:26am
I'm up close to 600 lift, but with Edelbrock heads if that makes any difference.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Sep/26/2018 at 5:45am
3/8 Cranes fit, 7/16 (if they still make them) do not.
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