FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: brra1961 on July 25, 2023, 09:25:23 PM
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for a 445 build with TFS heads not revving past 5400 and lift at .600 or under , thinking of running the factory non adjustables since I already have them , with end supports are they strong enough ? I'm not seeing the advantage of roller rockers other than less valve guide wear. reliability is most important to me and I'm hearing of broken aluminum rockers . does anyone have any experience using factory rockers over 500hp ?
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The first question that comes to mind is what valve springs are being used on the heads? Seat pressure, open pressure, lbs/in. A basic explanation can be found here (https://help.summitracing.com/app/answers/detail/a_id/4771/~/valve-spring-rate).
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I plan on using the springs that come with the TFS heads for hyd. roller
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According to TFS instructions for those heads (https://static.trickflow.com/global/images/instructions/tfs-56417001-c00_eg.pdf):
Valve springs, Standard:
1.460" O.D. dual spring with damper
128 lbs. @ 1.900" installed height
394 lbs. @ 1.175” open
390 lbs. per inch rate
.650" maximum lift
To my knowledge, shouldn't be an issue for the rockers themselves. If you use rocker studs and end stands, the only potential weak point would be the shaft. I believe that should be ok though as well. Be aware the ratio on the non adjustables is 1.73 vs the 1.76 ratio of adjustables and most after market rocker arms.
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I would keep the lift to a minimum with them, although I have ran ~.650" with shoe style rockers. The stands need to be modified with the TFS heads in order to get the geometry correct.
Here's an example of how well they work....
This setup is on a stock stroke 390 with TFS heads and one of my hydraulic rollers. Engine made 540 hp here on pump gas. Engine is in a Galaxie wagon, leaves at about 5000 rpm, shifts at ~7000.
As of last month, this engine/car had about 6000 miles and 247 passes on it.
(https://live.staticflickr.com/1769/42016145295_e2e3bc8b3c_z.jpg)
(https://live.staticflickr.com/65535/43496851405_39120e139c_z.jpg)
(https://live.staticflickr.com/65535/50053824641_c2e00c87f2_z.jpg)
(https://www.flickr.com/gp/148770020@N04/08004jb9j3)
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What camshaft specs are you running?
Running only to 5400 rpm with TFS head certainly shows an issue.
As Brent knows the high rocker ratio ford FE's and relatively heavy valves leads to issues with a somewhat aggressive
hydro roller cam.
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what type of " Issues " are you referring to ? I haven't specced the cam yet but am thinking just under .600 lift and in the 235 range at .050 , hyd. roller , I want to have good low end torque and throttle response. It will be going in a vintage desert race truck , 65 f100, C6, 456 gear, 35" tires. RPM, holley 750dp ,truck headers ,converter stall approx. 2800. Brent , what should I keep the lift under if running factory rockers ?
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235° at .050" will put you above a 5400 rpm peak if that's where you're wanting to be. Only takes 230-231 to get to 5500-5600 with a 445 and TFS heads.
For lift, I've ran the factory non-adjustable rockers at 440 lbs of open spring load and .630" lift. You can never get the shoe style rocker pattern to be as narrow as a roller, but you can narrow it up pretty good with some careful geometry checks.
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what type of " Issues " are you referring to ? I haven't specced the cam yet but am thinking just under .600 lift and in the 235 range at .050 , hyd. roller , I want to have good low end torque and throttle response. It will be going in a vintage desert race truck , 65 f100, C6, 456 gear, 35" tires. RPM, holley 750dp ,truck headers ,converter stall approx. 2800. Brent , what should I keep the lift under if running factory rockers ?
Sorry, I misread your post.
Engine flow demand for a 445 turning 5400 rpm Max is not very high. Ported 2 barrel heads would suffice. However you have already purchased TFS heads already. Brent can certainly get you in the ballpark for cam timing. I would think 210/218 @ 0.050 might be enough.