Press-in rocker arm studs migrating up.

I posted on “what have you done lately “ thread, but thought I’d start a legit thread here.

When replacing the valve seals (mid 70s 350, 461 camel hump heads, roller tip rockers, unknown cam with lumpy idle) I noticed some studs with more thread showing above the nuts. I took two rockers off and measured the difference between one with the most thread showing and the least. Honestly I thought I was checking for cam lobes that were going south. What I found was one sample stud measuring just over 1 7/8 showing, and the other just under 1 7/8 showing- that’s the difference.

There’s three on the passenger side that are like this, drivers side a couple as well in varying degrees. I didn’t notice them before, but it’s possible that I wasn’t observant. When I parked the truck to work on it, it wasn’t make any noise- and the visual stud difference is quite noticeable. After lashing the valves it seems likely that they were like that all along. It also is a possibility that one or more studs were replaced at one point and they’re not the same exact length. But more likely that they would’ve converted to screw in studs at that time.

My dad told me years ago that he had one pull out on his 327 and he just hammered it back in and it never made a peep again. @Ajax19 recommended a thread repair kit that looks good but would require yanking all the studs and retapping them, and also mentioned welding but I don’t know how to weld. That seems a lot of hassle for a set of heads that still wouldn’t be machined for guide plates.

I don’t think there’s much to be done except make the call myself. But sometimes you guys surprise me and have something that I never thought of- I suppose I could mark the rocker nuts with paint and readjust to see if they’re moving up any more.

I don’t want to sell my Halibrands, but if it means I have a set of good heads that won’t do this again, I’m all for it. Thanks in advance for any input.

Back in the day....WAY back, when I worked at the Chevy/Cad dealer, GM had a special tool that was a Rocker arm stud installation tool. Pull the studs, position the stud and pound the tool over the stud and seat them. It set the studs to the proper depth. I took it one step further and drilled the head and the stud and installed roll pins to hold them. Didn't have money to machine them or to buy the screw in studs and this worked!!! Continuously buzzed that 327 to 7500 and they never broke or pulled!!! YMMV

You changed geometry and probably tension. You should have went to screw in studs. BUT, in the old days, we drove them back in, drilled and pinned them with roll pins, as this could also be done on the vehicle, fairly quickly.

ChuckN said:

What I found was one sample stud measuring just over 1 7/8 showing, and the other just under 1 7/8 showing- that’s the difference.

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That is not enough difference to worry about. They are not as accurate from the factory as people think When they really start to pull out you will be able to see it at the bottom of the stud where it goes into the head.

I have a brand new set of Vortec heads here and I just measured them. There is almost a .060" difference from the highest to the lowest. Thats about 1/16"

I have been in the business for 35 years and have probably only seen 5 or 6 studs pulled out on Chevy heads.

BillK said:

That is not enough difference to worry about. They are not as accurate from the factory as people think When they really start to pull out you will be able to see it at the bottom of the stud where it goes into the head.

I have a brand new set of Vortec heads here and I just measured them. There is almost a .060" difference from the highest to the lowest. Thats about 1/16"

I have been in the business for 35 years and have probably only seen 5 or 6 studs pulled out on Chevy heads.

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Mine was due to high spring pressure from the Z-28 valve springs and high engine revolutions!!

BillK said:

That is not enough difference to worry about. They are not as accurate from the factory as people think When they really start to pull out you will be able to see it at the bottom of the stud where it goes into the head.

I have a brand new set of Vortec heads here and I just measured them. There is almost a .060" difference from the highest to the lowest. Thats about 1/16"

I have been in the business for 35 years and have probably only seen 5 or 6 studs pulled out on Chevy heads.

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Bill, here’s some pics, I didn’t want to continue without them, descriptions sometimes don’t tell a story. This one is the most obvious.

Compared with this-

Hard to grab on a camera phone, I know. Here’s a picture of the base of the stud on the one with most threads showing.

So it may be the case of finding something and just plainly becoming anxious over nothing. But I’ve heard horror stories so…

I should be getting on with more modern heads anyway. So that will still be on the list for this winter, just was trying to discern if this is a “now” problem or “it can wait “ problem.

@idahovette did you lose a bunch of them or just one?

I wouldn't worry about it at this point,they may have been like that for 20 years,drive it,pay attention to it,you'll here the lifters start clicking if they pull out any further. If the lifters start clicking then worry about it,and as others have said,pins are a cheap easy fix.

Ricko1966 said:

I wouldn't worry about it at this point,they may have been like that for 20 years,drive it,pay attention to it,you'll here the lifters start clicking if they pull out any further. If the lifters start clicking then worry about it,and as others have said,pins are a cheap easy fix.

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Thanks! Carry on, all. Probably been that way the whole time. I’ll update here if anything changes

ChuckN said:

@idahovette did you lose a bunch of them or just one?

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I lost 4 or 5, but under Heavy duty situations. Had a 56 Chevy 2 door wagon, with a standard bore 327, 11.5 to 1 pistons, the optional Z-28 solid lifter cam, tunnel ram with 2 600 holleys,(@Paladin ) munice, and 5.13 posi gears, 9.00x15 wrinkle walls Zinged it to 7500 consistently, ran mid to low 12s. So yeah it was a little stressed out.....Disclaimer....didn't have much money, so most of my stuff was what I could buy from my local Chevy dealer where I worked, so didn't have the "best" stuff..........but it as a LOT of fun....like my friend said "the most fun you could have, with your clothes on"!!!!!!!!!

idahovette said:

I lost 4 or 5, but under Heavy duty situations. Had a 56 Chevy 2 door wagon, with a standard bore 327, 11.5 to 1 pistons, the optional Z-28 solid lifter cam, tunnel ram with 2 600 holleys,(@Paladin ) munice, and 5.13 posi gears, 9.00x15 wrinkle walls Zinged it to 7500 consistently, ran mid to low 12s. So yeah it was a little stressed out.....Disclaimer....didn't have much money, so most of my stuff was what I could buy from my local Chevy dealer where I worked, so didn't have the "best" stuff..........but it as a LOT of fun....like my friend said "the most fun you could have, with your clothes on"!!!!!!!!!

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Man that’s awesome! Have any old photos laying around?

If the studs were pulling out there would definitely be some new valvetrain noise along with it. I believe you are seeing the effects of mass produced parts.

ChuckN said:

Man that’s awesome! Have any old photos laying around?

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Sorry, I'm late to reply. I may have some, but after moving in 2017, I'm still finding things my Bride packed away, so.......

77Dmax said:

If the studs were pulling out there would definitely be some new valvetrain noise along with it. I believe you are seeing the effects of mass produced parts.

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Thanks for the confirmation! Appreciate it. Seems fine since I’ve been driving it.