340 adjustable LOCKING rocker arm kit

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Well I thought you were being help but evidently somebody thought you weren't and eliminated all of the postings. What's the sense of helping somebody if they're just going to be deleted kiss my butt whoever did that.
It turned into a free for all. I deleted 23 posts some were even mine. Without knowing what rocker arm he has how can we help him find the proper adjuster? He dropped the ad and didn't come back to answer questions. I sent him a PM.
 
Looking at the picture it looks like the tip of the rocker arm is almost completely past the valve stem. Where did you get those rocker arms?
I see you shimmied the shaft.
 
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It wasnt a "free for all". It was informative as hell. There were good points to think about and make sure of. I'll even wager the OP was appreciative of the info put forth. He "dropped the ad"?? Who knows for what reason....
It turned into a free for all. I deleted 23 posts some were even mine. Without knowing what rocker arm he has how can we help him find the proper adjuster? He dropped the ad and didn't come back to answer questions. I sent him a PM.
 
You definitely need more than adjusting screws with nuts. Where did you get the shims that you put underneath the shaft? Were they too offset the Rockers or were they just to raise them up?
It looks like your rocker arm is rubbing against the valve spring retainer.
What kind of RPM are you expecting out of this motor? Does it have a solid lifter cam or a hydraulic?
 
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I actually only need the threaded adjusters with lock nuts for a stock 1970-71 340. I've checked many places only with a NO, don't have: Bouchillon, Jegs, Summitt, Mancini, Hughes. This is a pic of the first two bent CompCam pushrods. The adjustable rocker arm set is for the 273 engine and everything was new. Nobody had LOCKING adj rockers at the time so we went with these. 30 minute run time and the first 10 mile round trip and BAM! Can anyone help? Thanks

View attachment 1715954369
Thanks for the photo. Those look like stock rockers and the adjusters I posted a link to above (from Napa) are what you have. I see you have a bent pushrod. You have more issues than a replacement adjuster.

I am moving this thread to a different forum and will re-post the discussion. You have some bad going on there. That photo you just posted could have changed the direction of this thread. Just sayin.
 
Thanks for the photo. Those look like stock rockers and the adjusters I posted a link to above (from Napa) are what you have. I see you have a bent pushrod. You have more issues than a replacement adjuster.

I am moving this thread to a different forum and will re-post the discussion. You have some bad going on there. That photo you just posted could have changed the direction of this thread. Just sayin.
Which forum did you move it to?
 
The Chrysler rocker arm on the 273 and the 70 340, 6 pack do not have a lock nut they have a varying thread that causes the tension between the adjuster and the rocker arm that holds the adjuster in place when you adjust it. Now the thing that you do is you tap those rocker arms out to straighten those threads out and you put in the ones that use the nuts to lock them down. But you also want to take a flat file and dress the top of that area on the rocker arm where that nut sits otherwise it's going to back itself off. Here is the kit from jegs.

OEM 340 6-pak engines did have the machined pad and jam/lock-nut on the adjuster.

Got a few questions:

* Does the OP have hydraulic lifters? (273 pushrods are normally about .25"-.30" too long for hydraulic lifters.)
* Were the rockers shimmed because the pushrods were too long?
* Mis-adjustment and/or rocker-to-retainer interference could have contributed to the bent pushrod as well.

FWIW, I don't have any to compare side-by-side, but I believe some aluminum rocker manufacturers, like Harland Sharp, use the bigger adjusters.

8096651_orig.jpg
 
You definitely need more than adjusting screws with nuts. Where did you get the shims that you put underneath the shaft? Were they too offset the Rockers or were they just to raise them up?
It looks like your rocker arm is rubbing against the valve spring retainer.
What kind of RPM are you expecting out of this motor? Does it have a solid lifter cam or a hydraulic?
Those first two rockers are flopping around which allowed the pushrod to bend. This motor is for daily driving, never raced, little burnouts here and there. It's got a Sum-6901 Cam, 218/228@.050 .441 Lift, Engine Pro lifters HT-2011B
 
OEM 340 6-pak engines did have the machined pad and jam/lock-nut on the adjuster.

Got a few questions:

* Does the OP have hydraulic lifters? (273 pushrods are normally about .25"-.30" too long for hydraulic lifters.)
* Were the rockers shimmed because the pushrods were too long?
* Mis-adjustment and/or rocker-to-retainer interference could have contributed to the bent pushrod as well.

FWIW, I don't have any to compare side-by-side, but I believe some aluminum rocker manufacturers, like Harland Sharp, use the bigger adjusters.

View attachment 1715954426
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Your right my brothers 6 pack heads had the screw and nut.
I thought someone done swapped them out.
Thank you. I may not always be right but I'm never wrong. Lol
 
Those first two rockers are flopping around which allowed the pushrod to bend. This motor is for daily driving, never raced, little burnouts here and there. It's got a Sum-6901 Cam, 218/228@.050 .441 Lift, Engine Pro lifters HT-2011B
Not a big enough cam to bend pushrods unless they are too long. Loose adjusters won't cause something like that.
 
Jadaharabi,
Too many details out there for anyone to remember everything. Don't want to step on any toes, just trying to keep accurate information out there when I can. I've made mistakes too but appreciate constructive criticism/correction. There's always something more to learn.:thumbsup:
 
The problem is, PRW shows TWO different part numbers. One is clearly advertised as 7/16 the other is not so clear. There's no reason for two different part numbers in the same size, so it's gotta be a typo. One is 3/8 and the other is 7/16. You're probably gonna have to call someone at PRW that will actually WALK out in the warehouse and LOOK at the part.
Man, the Good Ole Days of Phone Calls AND Customer Service! Ahhh, brings back memories...
 
Email from Bill@PRW, when I enquired Nov of 2021


"Hello Steve,



PRW Mopar ball end and cup end adjusters are 7/16”-20 designed for PRW Rocker Arms with 5/16” ball or cup end pushrods. If you are looking for 3/8”-24 Mopar OEM Ball-Style Adjuster Screws, PRW does not have those to fit your application.



We do have strong lightweight Valve Lash Lock Nuts in 3/8”-24 (PRW PN: 1004502). These are available for your application and others that use 3/8”-24 adjusters. All PRW fasteners are SCM-4135 or 4140 alloy steel that are higher tensile strength than Grade 8.



I checked a few online resources and the parts you are looking for are not readily available from standard sources. I am confident that Manton Pushrods can help you. I have provided contact information below.



Ask for Robin or Trevor. Direct link to Manton adjuster screw applications is here: Adjusting Screws – Manton Pushrods"
 
OEM 340 6-pak engines did have the machined pad and jam/lock-nut on the adjuster.

Got a few questions:

* Does the OP have hydraulic lifters? (273 pushrods are normally about .25"-.30" too long for hydraulic lifters.)
* Were the rockers shimmed because the pushrods were too long?
* Mis-adjustment and/or rocker-to-retainer interference could have contributed to the bent pushrod as well.

FWIW, I don't have any to compare side-by-side, but I believe some aluminum rocker manufacturers, like Harland Sharp, use the bigger adjusters.

View attachment 1715954426
The lifters are Engine Pro HT-2011B for a stock 340, don't know why the shims were used and rockers, shims, adjusters came from Mancini. CompCam push rods 7821-16 7.389"x5/16". Also, the first two rockers a flopping around and I noticed, where i'm pointing, there is a small gap allowing those two rockers to slide left to right.

Rocker 1.jpg


Rocker 2 w gap.jpg


Rocker 3.jpg


Rocker 4.jpg
 
The lifters are Engine Pro HT-2011B for a stock 340, don't know why the shims were used and rockers, shims, adjusters came from Mancini. CompCam push rods 7821-16 7.389"x5/16". Also, the first two rockers a flopping around and I noticed, where i'm pointing, there is a small gap allowing those two rockers to slide left to right.

View attachment 1715954582

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View attachment 1715954584

View attachment 1715954585
The very FIRST thing you should be doing is asking your engine "builder"
 
I had same concern about side to side rocker movement. Advice from fabo was to have max around 0.020" side play.
Was this a fresh rebuild? Cam degreed?
 
I had same concern about side to side rocker movement. Advice from fabo was to have max around 0.020" side play.
Was this a fresh rebuild? Cam degreed?
Fresh EVERYTHING [read $$$$$] That's what makes this so effed-up. When you pay someone $5000 and then they want another $800 for a dynotune, that's BS, at least, I would think he would run the engine.
 
Fresh EVERYTHING [read $$$$$] That's what makes this so effed-up. When you pay someone $5000 and then they want another $800 for a dynotune, that's BS, at least, I would think he would run the engine.
You have mechanical issues with the build that locknuts on your adjusters probably will not fix.
 
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