5.9 Magnum PR Guide Plates

Hey folks,

I'm running EQ heads and using the Chebby style rocker setup. I have the Ede Magnum guide plates and the wipe patterns are atrocious. Vendor says they never line up perfectly, which is clearly true.

Has anyone used the Comp 4839-8 adjustable guideplates (or similar) with a Magnum head? They're listed for SBC but being adjustable, it seems like they could work.

A set of those and stud girdles will hopefully give me some confidence in my valve train.

Thanks in adv.

Comp has a guide plate made for the magnum heads. I had to sand all the Comp plates to get clearance, because for some reason they tightened up when i torqued down the studs. So if you go with those, be prepaired to "fix" them.

Me too & I'm mocking up & the rocker is too long on the valve side & the roller is almost all the way off of the valve (on ex side). Not sure how the guide plate or anything on that other side would affect this but I am in need of a solution also. EDIT comp cams 4825 plates, mounting hole & PR guide hole are both 5/16". had to get furd studs 5/16/3/8 cuz the CC ones did not have enough 3/8 stud length up top but I still have the W/P & rocker length to resolve, might need new rockers.

Looks like the same rockers I'm using, 1.65 ratio (Hughes 1550 kit). I can't get both rollers centered fore and aft on the valve. 1 or the other perfectly aligned, or pigeon toed. I think I'll be able to get mine satisfactory with adjustable guide plates.


My kit came with 5/16x3/8 arp studs. Number listed for some Ford, some Olds and Mopar Magnum.


If you're using reg Chevy 1.6 rockers, they'll be effectively 1.54 or something, and off even more if using 1.5's. I would think this would give the opposite problem to yours though.

Yeah, given the stud situation, my plan is to find an adjustable guide plate solution that will work and add the Jomar stud girdles. I get nervous pulling above 6K in the current state.

All that said, the advice I have been given from people using the Chevy style setup and SB Chevy people say pigeon toe will be fine and the girdle is overkill.

Mike at B3 sent me those rockers (I cant tell the brand) & the studs which were too short. I then got the Lunati Furd ones in the pic which are longer on the top 3/8 thread length & on the bottom 5/16 thread length then I mocked up but the roller is too far to the outside so I need to call him. I will go out & mockup a pair of rockers & the plate & see if the alignment is good if that info/the part #'s I have will help you. I ain't recalling any in or out pidgeon toed from last weeks checks but I will check. EDIT with 1.5 rockers which side of the fulcrum is shorter, the pushrod or the valve side? & I did not get any paperwork with these rockers so I dont know if they are Hughes' offerings or not. Dwayne poerter "fast68plymouth" picked the cam for me with my 1.6 rockers so if 1.5 is a solution that would make the cam milder but maybe it would help the wipe pattern contact, not sure the solution yet just thinking out loud till I get it solved.

Keep thinking out loud! I have the Ede 9662 plates, don't have time to figure out how to post a pic at the moment.

If you take a look though, the stud holes are elongated and a bit larger than the stud, so maybe with those you could push your roller back on the valve stem with the plates???

I get told that I am thinking too much! (near daily) I had a 2 hr conversation with Mike (B3 racing) this afternoon & I am going to pin down how far out the roller is on the tip & he said if it ain't closer than .100" of the edge I "likely" can get by but to check the tip after the first race but that I might need to relocate the stud hole with an end mill/sleeve then a 7/16 stud (which I ain't willing to do right now). I didn't get out there to mockup today but tomorrow looks good. I still have the light springs in there now & not sure if that will load it enough to produce any pidgeon toed splaying that could happen but I will see what I see tomorrow for you & holler back.

get to the B3 website and read all 4 tech articles
you need to get the mid lift geometry right then the guide plates

I got the Eddie heads, rocker arms, guide plates and pushrods from Hughes. Everything bolted together nicely, but I did have to reposition the guide plates a few times to get them right. No grinding required though.

I have my transmission out for a refresh and ordered a set of Jomar stud girdles to install. They are not on their web page yet, but they are available. It will be interesting to see if the reduced deflection is actually noticeable.

Basically the same here on the Hughes kit, though I'm using EQ heads. Still though, the rocker tips have a wonky tip placement and wipe pattern, though they fit the .100" from the edges of the stem L-R Robert mentioned, the rollers are completely on the stem throughout travel, they are not centered fore and aft.

On my install, they are not off enough to adversely affect performance per Hughes advice, but the wipe patterns are not perfectly centered on the valve stems like we like to see. Hughes told me they're never perfect with this setup and basically split the difference until they're both as close as possible. They're experience seems to be that as long as both rollers stay completely on the valve stem through the entire open/close sequence (and all other clearances are good), good enough. Mine most definitely do. But the wonky wipe pattern and fore and aft off center condition bothers me.

Best I could get from Hughes is that they like the Ede plates the best, though all those on the market have their warts. No response when asking about adjustable guide plates.

Hughes says no need for the girdles below 7K (or so) but given the 5/16x3/8 stud setup, it will have a nice placebo effect on me. Mathematically, my setup has the power dropping off by 6700 (though no strip or dyno time to confirm the exact RPM yet) so theoretically not necessary.

I may just keep an eye on the situation and let this dog lie as future plans for the heads include a wide mouth port job which will of course require valve train modification.

FWIW Here's what I have (pushrods not in) so the roller looks way further in than it actually is (with everything mocked up ready to go). the guide plate slots are .3330" and the 5/16 pushrods are .3115". Not sure this applies to your dilemma but this cannot pidgeon toe (as is).

Thanks Robert, variations on your third picture is how all my cylinders look with the valve closed. My pigeon toed description may have been a little extreme. Mine center up as the valve opens, then back to this.

An adjustable guide plate I think would center those right up perfectly.

Then the question returns as to whether it is going to get me anything as far a longevity, etc., or just satiate my inner A&P.

Rationally, all indications are that this should be fine, given my engine's duty cycle.

As to your dilemma, while our rockers look the same, I suspect you may have a strait up Chevy rocker, not one that is 1.65x (as mine say on top). My understanding of the extra ratio is that it makes up for the lifter bore and pushrod angles so it is a true 1.6 in operation on a Magnum engine.

I wonder if that .05" or so of extra ratio actually comes from moving the fulcrum toward the roller tip? Hashing that out and swapping rockers would be easier than reworking the heads to use 7/16 studs in my little garage. It doesn't look to me like there is enough meat on the boss (for me anyway) to not be worried about cracking given the spring pressures we use.

Why does it look to me like those pressed in pins are ready to pop out of the rocker tips?

There shouldn't be any stress on the guides. Why couldn't you just cut them in half, spread them as necessary, and weld them up for better pushrod alignment?

Yes I dont wanna end mill out the holes. Yes I believe these are straight up chebby items. If you have a part # for some with with a shorter fulcrum length on the valve side let me know & I will get one & mockup. & good eye on the pressed in pins (thank you), I will check em.

Here's the setup I have. I don't see them individually listed, unfortunately. I bet the would set you up with one, Hughes has really been a pleasure to deal with.

http://www.hughesengines.com/Index/produ...mp;partid=25405

I don't know for sure, but I think these are PRW's I haven't admitted to needing reading glasses yet, so I can't tell for sure from the makers mark.

Incidentally, I got my set from Mancini when they were having a sale.

Also, if time allows, I plan to pull my rocker boxes this weekend for an inspection. If I'm able, I'll take a couple of pictures.

Upon edit, I'm a daisy if these ain't them...

http://store.prw-usa.com/0236006-dodge-3...el-rocker-arms/

I'd bet the Chevy 1.65 is the same for almost $50 less.