426 hemi rocker arms

Posted By: cownurse

426 hemi rocker arms - 11/14/14 02:52 PM

Hi all,
Can anyone tell me how much spring pressure, the mopar performance non roller rocker arms can handle.

Posted By: Mopar_Rich

Re: 426 hemi rocker arms - 11/14/14 08:06 PM

The rocker arm itself can handle a lot of spring pressure (I have seen 750 lbs). It's just a maintenance matter of wear on the valve tip end. You need lash caps and they wear the rocker ends.

Back in the day, racers ran these pressures all the time.

Posted By: cownurse

Re: 426 hemi rocker arms - 11/14/14 08:32 PM

Thanks Rich, is it you who wrote the book.

Posted By: an8sec70cuda

Re: 426 hemi rocker arms - 11/14/14 08:38 PM

I don't know what spring pressures, but I remember HemiFred saying he ran the factory wide pad rockers for years and years on some pretty nasty roller cams.

Posted By: Mopar_Rich

Re: 426 hemi rocker arms - 11/15/14 12:19 AM

Quote:

Thanks Rich, is it you who wrote the book.

Yep.

Posted By: quickd100

Re: 426 hemi rocker arms - 11/15/14 02:20 AM

I've been running 740#'s over the nose with stock wide pad rockers for 4 years on the street. So far I've had one pushrod split a cup. Everything is coming apart again this winter for inspection though.Dave

Posted By: astjp2

Re: 426 hemi rocker arms - 11/15/14 09:48 AM

The problem is not strength, its consistency of the ratios. You can pick 100 rocker arms and be lucky to find a match set of 8, not the right ratio mind you but at least they would be the same ratio....Tim

Posted By: cownurse

Re: 426 hemi rocker arms - 11/15/14 10:54 AM

Thanks for the replies, seems to be a vast amount of knowledge in this forum.

Posted By: quickd100

Re: 426 hemi rocker arms - 11/15/14 12:46 PM

Quote:

The problem is not strength, its consistency of the ratios. You can pick 100 rocker arms and be lucky to find a match set of 8, not the right ratio mind you but at least they would be the same ratio....Tim

Very True!!! It's one of the hair pulling, cussing and screaming aspects of building a Hemi. I've got 2 sets of stock rockers one of which was a set of old superstock rockers. My intakes go from 1.63 to 1.69 ratio. The exhausts go from 1.49 to 1.53. Dave

Posted By: chryco

Re: 426 hemi rocker arms - 11/15/14 03:24 PM

Save up and just get these ........................

Posted By: 572charger

Re: 426 hemi rocker arms - 11/18/14 01:35 PM

agreed with chryco !!!! ive had them for over 10 yrs on my 700+ lift roller cammed hemi still look new no wear in 8000 + miles and many 9 sec passes and some 8 sec no2 passes !!!

Posted By: DaveRS23

Re: 426 hemi rocker arms - 11/18/14 05:55 PM

Quote:

Quote:

The problem is not strength, its consistency of the ratios. You can pick 100 rocker arms and be lucky to find a match set of 8, not the right ratio mind you but at least they would be the same ratio....Tim

Very True!!! It's one of the hair pulling, cussing and screaming aspects of building a Hemi. I've got 2 sets of stock rockers one of which was a set of old superstock rockers. My intakes go from 1.63 to 1.69 ratio. The exhausts go from 1.49 to 1.53. Dave

If my math is correct, then the variation between the rockers is less than 1%. How large of an impact could that realistically have for most of us? Is that range typical of OE style rockers?

It would seem to me that the head ports would not be that consistent.(even after porting) Or the intake runners. Or the cam lobes. Etc, etc. And I doubt that many of us could set the lash within 1%. A .001" variation on a .020" lash is 5%.

The OE style rockers have proven themselves to be very durable over the decades for most of what we do with these engines. So, how much real world impact does the infamous variation have on our combos. Could it be noted on a time slip or dyno sheet? Let alone seat of the pants?

Opinions please.

Posted By: quickd100

Re: 426 hemi rocker arms - 11/18/14 07:48 PM

That's my 'Good' set. the other set isn't worth talking about. Dave

Posted By: Cab_Burge

Re: 426 hemi rocker arms - 11/18/14 07:59 PM

I use to race(1974 to 1976) a 1970 426 hemi Cuda 4 speed car in NHRA stock, I ended up buying all the spare parts I could

I ended up finding out later that the rocker arms on my motor had .100 net lift difference(.430 to .530) on the exhaust side and .080 (.460 to .520) on the intakes

I went though five sets of rocker to get my motor legal with the stock cam specs, the ratio are horrible on the stock stuff

I like to get all things equal as far as compression ratio, storke, intake and exhaust port volume, combustion chamber volume, rocker ratio, net lift at the retainers and so on

Posted By: rowin4

Re: 426 hemi rocker arms - 11/19/14 01:31 AM

The interesting part of it is that after 40 + years the stock Hemi rocker arm set up is still selling for a average of $1500. bucks. :

Posted By: astjp2

Re: 426 hemi rocker arms - 11/19/14 01:42 AM

That is due to lack of knowledge and 4 important letters: HEMI

Quote:

The interesting part of it is that after 40 + years the stock Hemi rocker arm set up is still selling for a average of $1500. bucks. :

Posted By: Mulehead

Re: 426 hemi rocker arms - 11/19/14 01:45 AM

Same here

Posted By: DaveRS23

Re: 426 hemi rocker arms - 11/19/14 01:58 AM

Quote:

I use to race(1974 to 1976) a 1970 426 hemi Cuda 4 speed car in NHRA stock, I ended up buying all the spare parts I could I ended up finding out later that the rocker arms on my motor had .100 net lift difference(.430 to .530) on the exhaust side and .080 (.460 to .520) on the intakes I went though five sets of rocker to get my motor legal with the stock cam specs, the ratio are horrible on the stock stuff I like to get all things equal as far as compression ratio, storke, intake and exhaust port volume, combustion chamber volume, rocker ratio, net lift at the retainers and so on

Holy crap!

So, is it worth it to have some of the rocker guys to square up the ratios on the stock rockers? I think it is like $500 or so to do it. If, like me, you already have a good set of stock rockers, would getting them trued for that kind of coin be worth it versus $2,500 or more for aftermarket ones?

This would be for a street/strip car.

Between this and the threads on addressing the intake sealing issues, I am learning a ton here.