408 with stock rocker arm assembly?

[Duster_71]

Building a 408 with “J” heads and seeking advice on the Rocker Arms. Builder I’m working with recommends upgrading to a new set of PRW roller rockers and pushrods. Cost has me reluctant to sign off and considered using the old rocker arm assembly and push rods or look at a set of HD stamped rocker arms from Mancini Racing. I’ve seen some pictures from failed factory rocker arms and think at a minimum I should be looking at the HD rockers from Mancini. So, the question, risk the old rocker assembly or get the HD rockers and run with that or just bite the bullet and move up to the PRW’s?

 

[Sedanman]

Try putting up a wanted ad and see what you can come up with. A set of factory adjustable arms are probably better than the PRW stuff and cheaper.

 

[72Dart6pack]

Mopar made millions of rocker arms. With that many their will always be some failures. But the risk is not something I'd worry about. Save your money and stay with stock. Spend the savings on your family.

 

[IQ52]

It's kinda hard to suggest a rocker arm not knowing the camshaft you are using.

 

[Duster_71]

It's kinda hard to suggest a rocker arm not knowing the camshaft you are using.

We have not settled on a cam yet as it will be impacted by the selected rocker assembly. Given that, do you have any information or opinion to share?

 

[moper]

I built a 422 some years ago. Runs the H303-2 Crane hydraulic and 596 heads I ported. The cam mandates dual springs. I used custom pushrods from Manton on it with stamped steel he Mancini rockers. It did not run well with them. Customer switched to Crane rollers and the correct pushrods for them and it's been 9 years and 20k with no issues. If you have to run a double valve spring (vs a single with a flat wound dampener) I would plan on adjustables. I also like Isley or Crane sinterd iron.

 

[IQ52]

Is the engine already built, being built or still in the design stage? 'Cause with the information I have, it sounds to me like this is bassackwards.

 

[cannucky]

We have not settled on a cam yet as it will be impacted by the selected rocker assembly. Given that, do you have any information or opinion to share?

Your putting the cart before the horse .The cam determines the spring pressures which in turn determines the load on the rockers which will tell you if you need to upgrade over stock .Maybe try listening and learning .The first was information the second was opinion .

 

[mopowers]

The only info you've given is 408 with factory heads and you're asking for a rocker arm recommendation. More info needed!!!

 

[Duster_71]

Your putting the cart before the horse .The cam determines the spring pressures which in turn determines the load on the rockers which will tell you if you need to upgrade over stock .Maybe try listening and learning .The first was information the second was opinion .

Thanks, I get that. The cost of the cam and springs are about the same either way I just have to determine if I want to fork out the additional cost for upgraded roller rocker assem and push rods.

 

[yellow rose]

Yes, you can use the PRW rockers.

If the geometry is corrected they will be fine. But, you must correct the geometry.

I would never build a stocker with stamped steel rockers, let alone something for performance.

 

[cannucky]

Nobody is talking about cost .We are trying to explain that the cam dictates the spring pressure which in turn dictates how strong your rockers need to be ffs .Price has nothing to do with strength and mechanical efficiency . High lift and big duration cams require stronger springs than a stock flat tappet.You want power you need flow , a big part of getting that flow is the cams lift and duration so thats where you have to start .Pick a cam then build the valve train to suit that cam not the other way round .

 

[nm9stheham]

The decision process is:
1. Overall performance and use of the engine. That drives:
2. Cam choice for lift and duration, etc. That drives:
3. Rocker setups that can and cannot be used.

To answer the question another way, yes, you can use stock rockers, but it will limit the cam you can use. Now you need to know the limits of the stock rockers......

 

[rigger3006]

i have the mancini heavy duty rockers and thicker pushrods, 284/484 cam, during an overzealous 7000 rpm burnout i managed to poke pushrods through both rockers on #2 and blow a head gasket on opposite side. as long as you dont abuse your engine too much,heh heh heh, the mancinis will work, depending on cam choice of course

 

[diymirage]

Consider ease/cost of replacement down the road
I would spend the money on the bottom end and leave the rockers for later
(That is how my 408 is build, good bottom end with possibilities of upgrades by the heads)

I run a mild cam and stock rockers