First small block Mopar build More than a little nervous

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popinsmoke

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So after running brand X for years, I took the plunge and started running not one but 2 Mopars.
I have always been a fan but you can build brand X for pocket change and get parts at your local 7-11.

I am in the slow and tedious process of building an LA based 408 stoker, I had the short block done local and at the moment it is a great ornament sitting on the stand in my garage.

As money permitted I have gathered the other parts I need, however now I am second guessing myself on if I understand the small block mopar valvetrain to assemble the engine.

I have read all I can get my hands on but my brain is stuck on brand X valvetrain, I have the feeling that I might be overthinking it, but the more a read about the geometry the more I get confused and feel that I might have bitten off more than I can chew.

There is allot of great information on this board, some of the tech write ups are amazing! Can anyone point me to a good source of information on setting up the small block valve train, I have zero experience setting up a non adjustable shaft mounted rocker set up.

I know that at some point to have to just jump in and learn as you go, however I am trying to avoid costly mistakes and I know that this is old hat for many of you.

Thank you for your time and consideration.
 
What is your question or questions? Welcome aboard,we are a helpful bunch if you ask questions
 
popinsmoke said:
So after running brand X for years, I took the plunge and started running not one but 2 Mopars.
I have always been a fan but you can build brand X for pocket change and get parts at your local 7-11.

I am in the slow and tedious process of building an LA based 408 stoker, I had the short block done local and at the moment it is a great ornament sitting on the stand in my garage.

As money permitted I have gathered the other parts I need, however now I am second guessing myself on if I understand the small block mopar valvetrain to assemble the engine.

I have read all I can get my hands on but my brain is stuck on brand X valvetrain, I have the feeling that I might be overthinking it, but the more a read about the geometry the more I get confused and feel that I might have bitten off more than I can chew.

There is allot of great information on this board, some of the tech write ups are amazing! Can anyone point me to a good source of information on setting up the small block valve train, I have zero experience setting up a non adjustable shaft mounted rocker set up.

I know that at some point to have to just jump in and learn as you go, however I am trying to avoid costly mistakes and I know that this is old hat for many of you.

Thank you for your time and consideration.
Click to expand...
What head are you using?
 
Don't get discouraged over over think things to much. So your research and remember ever body is going to have a different opinion. As for my experiance, unless you're building a max effort engine, stick with stock type, but quality valvtrain parts. You don't need exotic parts to spin 6500 on a moderate street strip Mopar. I've got a solid lifter 340 built 30 years ago running single springs, 273 rockers and pusrods and turns 7500 at anytime reliably. Take your time. Triple check everything and stay away from China parts. You be fine
 
Blue printed engines only require tightening the rocker shaft pedestal bolts. Done deal.
 
If your looking at a suggestion on a brand id recommend prw roller rockers. Have a set of the prw alloy steel roller rocker arms and shaft kit. No issues. Not sure on the correct installation procedure as it will vary slightly from manufacturer to manufacturer but just thought id throw that out there. I have a motors manual at home ill look and see if it has any info in there.

IMG_1376.JPG
 
71DodgeDemon340 said:
If your looking at a suggestion on a brand id recommend prw roller rockers. Have a set of the prw alloy steel roller rocker arms and shaft kit. No issues. Not sure on the correct installation procedure as it will vary slightly from manufacturer to manufacturer but just thought id throw that out there. I have a motors manual at home ill look and see if it has any info in there.

View attachment 1714999847
Click to expand...
How much were those prw rockers? Use std pushrods? How long have you been running them?
 
Whole kit lists for 545.00 now. Ive been running them in my 340 for about 5 years plus the multiple pulls on the engine dyno. They make a billet aluminum kit for right at 500.00. They may have went up but I believe i paid around 450.00 or 500.00 for the alloy steel kit around 5 years ago. Cant remember what brand or length pushrods were used, i left the hydraulic lifters and push rods up to my engine builder. Im sure they used a name brand, but couldn't say for sure

They also come in 1.5 and 1.6 ratio
 
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Do you know if they are the ball end push rods or the cup end t
Like the old 273 adjustable?
 
Sedanman said:
What is your question or questions? Welcome aboard,we are a helpful bunch if you ask questions
Click to expand...


Hey Sedanman,

PM me if the guy you sold the X block to wants or needs the paper work on it. There ain't no way I'm going to learn how to do it. If he wants a copy, I'd be happy to burn a copy and snail mail it to him. That I know I can do.

Let me know.
 
Thank you for the replies,

Yellow rose, I have read the articles you linked part of the reason my head is swimming. I have a adjustable push rod for checking the proper push rod length, as I understand it push rod length is critical since the stock rockers are non adjustable.

I will be using RHS LAX heads as soon as I can source the correct head bolt as it seems the correct ones are neither LA or Magnum style.

Where I am foggy is the correct step by step procedure for setting the valve train up with the proper lifter preload and ensuring the correct geometry throughout the rocker arm travel.

My cam is mild .477/.480 from my research the stock rocker system is more than capable in this lift range as long as push rod length is correct.

I do tend to overthink things, I am pretty handy with a wrench, however with a new system that I am not familiar with I like to have a tech manual of experienced oversight so those rookie "well now you know" moments are avoided.

The SBM is too pricey to learn from my mistakes and prefer to do things right so you only have to do them once.
 
I got a motors manual at the house and ill look and see here in a bit when i get home and see if it has the procedure for the factory style
 
If you are familiar with brand X then this is the proper LAX set up for .650" lift and 8,200 rpm. I'm in the process now of going from a 1.94" intake to a 2.055" intake
2010 Mopar Nats and Chenoweth contest engine 037.jpg
 
yellow rose said:
Hey Sedanman,

PM me if the guy you sold the X block to wants or needs the paper work on it. There ain't no way I'm going to learn how to do it. If he wants a copy, I'd be happy to burn a copy and snail mail it to him. That I know I can do.

You can just take a pic of it and post the pics too
Let me know.
Click to expand...
 
popinsmoke said:
Thank you for the replies,

Yellow rose, I have read the articles you linked part of the reason my head is swimming. I have a adjustable push rod for checking the proper push rod length, as I understand it push rod length is critical since the stock rockers are non adjustable.

I will be using RHS LAX heads as soon as I can source the correct head bolt as it seems the correct ones are neither LA or Magnum style.

Where I am foggy is the correct step by step procedure for setting the valve train up with the proper lifter preload and ensuring the correct geometry throughout the rocker arm travel.

My cam is mild .477/.480 from my research the stock rocker system is more than capable in this lift range as long as push rod length is correct.

I do tend to overthink things, I am pretty handy with a wrench, however with a new system that I am not familiar with I like to have a tech manual of experienced oversight so those rookie "well now you know" moments are avoided.

The SBM is too pricey to learn from my mistakes and prefer to do things right so you only have to do them once.
Click to expand...

It's really pretty easy with the stock valvetrain setup, as long as the valves are stock length. Also, make sure the valve stem heights are equal within .020" max. Bolt the rockers on the head with an adjustable pushrod in place, and the lifter on the heel of the lobe. Adjust to ZERO lash/preload. Remove rocker shaft, measure pushrod and add .040" to the measured length. Order pushrods at that length. If any of the preliminary checks are out of stock spec, you should probably give me a call.

The factory geometry should be really close in your case, unless of course the valve stem heights are off, ie longer valves.
 
The upside - in a shaft system the only thing that pushrods effect is lifter preload.
The downside - proper rocker geometry is only set by the guy doing the valve job as Mike said above.
 
Ok here we go per the motors auto repair manual. If anyone see that i missed something or info is wrong please dont hesitate to correct or add to this.

273, & 1967-72 318,340,360

To provide correct lubrication for the rocker arms on these engines, the rocker shafts have a small notch machined at one end, Fig. 7 below, and these notches must always face inward toward the center of the engine when installed. In other words, the notched end must be toward the rear of the engine on the right bank and toward the front of the engine on the left bank.

Rocker arms must be correctly positioned on the shaft prior to installation on cylinder head. A good way to do this is to place each rocker arm on the shaft so the adjusting screw is on the same side as the notch of the shaft when rocker arm is right side up.

It is also important when installing the rocker shaft assembly on the cylinder head to position the short retainers at each end and in the center, and to place long retainers in the two remaining positions.

Valve arrangement. Front to rear

273,340,360: E-I-I-E-E-I-I-E

Locate the assembly on the cylinder head and position rocker arm adjusting screws in push rods.

Tighten bolts finger tight, bringing retainers in contact with the shaft between rocker arms.

Tighten bolts to specified torque.

1968 340.

Rocker arm shaft bracket 15 ft lbs.

Rocker arm cover 36 inch lbs.

1969-72 340.

Rocker arm shaft bracket 210 inch lbs.

Rocker arm cover 36 inch lbs.



After running the engine to normal operating temperature, adjust valve lash to specifications.

Valve lash on 340 is hydraulic and there is no adjustment.

V8's with mechanical lifters.

Engines with mechanical lifters can be identified by the rocker arm adjusting screws. These screws are self locking and when turning them during the process of adjustment they should indicate some resistance to turning
(a minimum of 3 ft lbs of tension).
If any screw turns too easily it should be replaced and if necessary the rocker arm as well.

Valve clearances should be set up after the engine is warmed up to operating temperature and to the clearances listed below.

Checking hydraulic lifter static clearance:

After performing a valve guide job or replacing a cylinder head the hydraulic lifters should be collapsed and the valve stem-to-rocker arm clearance checked. Each lifter should be checked individually to guard against differences in machining or wear variables.

Valve stem-to-rocker arm clearance should check within limits given below.

1968-72 340.

Stem clearance

Intake: .001-.003
Exhaust: .002-.004

If the actual measured clearance is less than the minimum specified, very likely the valve has been ground down too much and a new valve should be installed.

When the actual measured clearance is more than the maximum specified, the valve face should be ground down further to bring it at or below maximum static clearance specified.

To check the clearance a special spanner type tool is commercially available to apply pressure on the rocker arm to bleed down the hydraulic lifter until the plunger is completely bottomed. Of course, checking must be done with the lifter on the heel of the cam. If the special tool is not available, a stiff rod, such as a socket extension and a length of wire can be used to collapse the lifter. Wire one end of the rod to tge rocker arm as close to the valve as possible and apply presure to tge other end until lifter is collapsed.



Fig. 7


IMG_1377.JPG


Hope this helps
 
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Gentleman,

Thank you all for your replies after much reading and some excellent information I sourced from this site, I feel much more confident that I might just get this right the first time or at least the third :)
 
I would not tighten the rocker arm shaft bolts that tight, I just always gave them a good snug.
Sorry not too technical but I have seen a few of those bolts snapped off.
 
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