EQ mag heads. the comp cams rocker studs 4504-16, the lower 5/16 stud length is .680" and the Lunati 86004-16 studs have a .750" lower 5/16 stud length. these are quality black items (grade 8 or better I would think). I have both sets cuz I needed more upper (above the boss) (3/8) thread length to get my geometry dead on & the Lunati has 1&3/4" up top & the CC has 1&1/2" up top. My 1&3/4" installed height (.100" longer) valves are giving me setup problems & even the Lunatis I might need to shim them up off of the head bosses. My Question is: how much thread engagement down below into the head bosses must I keep to have the max strength against breakage (5/16 coarse threads). I can shim up the Lunatis to how much the CC ones are (.070" gain) which will get me "close" but I may need a bit more so I am wondering how much actual length does that 5/16 stud need for max strength? so I ain't risking breakage especially with these smaller 5/16 studs. thank you for your time.

I think you will find that anything greater than
the stud length will give you the max strength
of the stud but then it comes down to the strength
of the alum around the stud being that they are
hardened studs

these are iron heads. iirc 1&1/4 or 1&1/2 times the bolt dia for a length dimention is needed for max strength but I ain't sure on those 2 numbers

Just stud length.. think about it.. anything
over the stud dia is just wasted length(its
hanging out in space)

Alright it sounds like I have plenty of leeway, thanks Mr P

1.5 times the diameter or 8 threads will usually give you full strength. In aluminum engineers sometimes go 2x the diameter.

That means I have plenty of length to work with & possibly even the shorter studded CC ones will suffice. Thanks Andy & I was just perusing your book wondering if I can weld a dial indicator to a retainer to check scrub like I saw pictured there.

If its 1.5 times then why do they say at least
the stud dia on wheel studs has to be sticking
past..thats why I said at least the dia.. I
never heard that 1.5 times even in the fastners
lab

1x diameter on steel will work if everything is perfect. Most of the times not everything is perfect so the rule of thumb is 1.5x diameter. With aluminum you want a little more thread engagement so 1.5 to 2.0 should work. If you're working with plastic or wood then you want even more thread engagement. Really high strength steel with carefully machined threads you could get by with less than 1x diameter but it could be marginal. The engineering answer for any question is "it depends".

If my figuring is right to go 1.5X I can raise the CC ones .212" which will put em (in effect) at .892", which is significantly longer than the Lunati .750 ones that are "almost" long enough so I should be plenty good (& have the Lunatis' for a future build. I'm pumped! & I needed this after the preload/wipe pattern/vp clearance dilemma I am haveing with this. thanks again guys.

1 (as andyf says) 1.25 1.5 is for the stud into steel
more for cast iron or aluminum and how robust is the top of the casting where the stud goes in- some are quite small diameter
bottom tap and what do you come up with?
5/16 ugh
is the boss machined flat where you can seat a stud with a big hex
I do not like straight 5/16 studs
in a perfect world measure the casting and drill on a mill and retap to 7/16 as deep as the casting will allow-
you can also relocate the stud to better center the rocker over the valve stem (get your mid lift done right first)

I used the lunati longer ones (5/16 & 3/8) & the up top 3/8 stud part is 1&3/4 (iirc). Down below it has way more than 1/2" thread length engagement on the bottom 5/16 stud section. With an 8" pushrod I can get minimal (OK) (~.020) preload with the rocker screwed down 6.2 turns (from 90 deg at zero lift per the straub vid with the cam lift I have) so there is a 90 deg angle at half lift. THE PROBLEM is the 1.6 chebby stud mounted roller rockers are too long & the roller is way too close to the outer (exhaust) edge of the valve. I dont want to at the moment relocate the stud & even if I did it would highly likely on the other side make the pushrods rub on the wall (they're close now) & I might even as is need to slightly file the pushrod wall to thin it slightly for a hair more clearance.

The more engagement you can get the better. The studs are much stronger than the iron or aluminum. Its not wasted, its insurance. Anything you can use studs on is a gain. And as much engagement as possible.

Insurance and helps the flex and vibration
chevy rockers are longer fulcrum to roller
mopar rockers are short
longer is better
you can get higher ratios when you backset
what about the crower's with the back-set fulcrum
it is more important to have the geometry right than the roller centered
that said it cannot go too near the edge
higher lift cam you have to lower the fulcrum compared to stock (which helps move the contact point toward the intake side) (or use a lash cap if you can't lower the fulcrum
grinding pushrod clearance is a fact of life with MOPARS

Robert, this would seem to confirm what we were discussing on the guide plate thread about fulcrum to roller distance.