Just how much punishment and lift can the stock rockers etc. Take? With 5/16 bolts, it makes me a bit uneasy. I wouldn't want to invest in a cam with XE lobes for instance, if the stock parts will fail or have a real short life. I don't have my motor assembled yet, so now would be the time to upgrade to 3/8 by 3/8 studs and sbc rockers. What have you run with success?
Magnum valve train; how strong?
- Thread starter gregsdart
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moper
Well-Known Member
No dog in this fight - I don't like Magnums in terms of return on investment unless it's a very mild build. But - there are plenty of XE hydraulic flat tappet cam engines running just fine out there. The valve spring height limitation determine the cam you can use. And there's not much of a choice for a cam of any real size as a result. I would ay if the spring you have for them fits and will work with your camshaft, don't worry about the strength of the hold-down bolts.
replicaracer43
Grumpy Old Man
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ARP also makes a nice set of hold down studs for them, should be stronger than stock
You could also uograde to a 3/8 stud with a drill and tap. I don't know if your into the extra work on that end. But if you do, while your there, extra spring clearancing could be done.
Depends on how deep you want to get into this.
Depends on how deep you want to get into this.
I am debating just how far performance wise I want to take this. It started as a low buck deal, and now it has grown to. Scat 408 stroker and EQ heads with mods. The heads are still at the machine shop so if I decide to go crazy here, they will get to do the drill and tap, and it sounds like Scorpion 1.7 rockers would be a good choice. Again, not sure how far I want to go, just collecting info. What ever I do, it will have to hold up to cruises of 120 miles round trip , running about 3,000 rpm.
Would be interesting to see if there have been any 5/16" stud failures and at what spring pressures used etc AND as well as any failures from drilled and tapped rocker pedestals for using 3/8" studs. Mostly all I saw when I was concerned was "theories". Surely there have been some failures. But at what spring pressure, lift and use? I like 5/16" studs and having as much meat in the pedestals vs. reducing the pedestal material, I'm using Comp Cam 5/16" studs in EQ magnums, with about .517" lift via 1.6 roller rockers, and Hughes 300# springs.
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To put it in perspective, the Magnum valve train is as strong as a 5/16 hardened bolt.
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