In the past I collected a few sets of Mopar Performance P4529706AB stock replacement exhaust rockers.

My 572 mockups had all been done with the same pair which both measured at 1.5225 ratio.
.609 lift on a .400 lobe without any deflection (light checking spring).

After reading the horror stories here regarding ratios being all over the place I was interested to
check some more and see what I could find.

I'm partially through the second set (have tested 10 so far).
The worst ones are 1.52. The best ones are 1.5225.

In every instance where I thought I had identified something a 1.51 or less, I found an error with either lash adjustment, indicator setup or both.
And in every case when those errors were corrected, the rocker ratios measured at least 1.52.

Note I have no current affiliation with MP, only several years of past work history.
If these parts were junk, I'd say so.
They're actually quite good....or at least, these particular ones that I have are rather decent.


I might go and check some more of them just because, but I see how this is probably going to go, and
may spend my spare time doing something more productive

I will check a few once I get it set up with the springs I am going to use and so on, and try to get an idea of deflection and so on.

I'm the luckiest guy around too I think. I've read the horror stories and have been checking the stock style Hemi rockers in my engines for over 20 years and always found them to be pretty darn close as well.

I'll also say this is with an import indicator and only .001 resolution, which prevents me from seeing much of anything in
between 1.52 and 1.5225 because with this combination there is only .001" difference in valve lift between the two.

I do have other (USA) indicators with higher resolution, but they all have shorter travel than my gross lift so
they wouldn't be useful here.

I'll be interested in seeing how much deflection you find between measuring with a soft checking spring vs the spring that will be used.

Im looking forward to the detective work as well.

Though I imagine I should be able to observe some sort of a loss from angled pushrods, how it shakes out is
Another thing.

I'm with Brad. When you load them with springs they will lose some ratio.

I've checked Hemi rockers. All were under 1.5 but they were very consistent.

I have checked many MP W2 rockers and all of them were 1.5 or a skosh higher with spring load. IIRC, they were 1.58 with checker springs. The Norris stainless rockers for W2 heads I had would measure 1.66 with soft springs and 1.60 with spring load.

Ive checked my stock hemi ratios based on what ive read here also. They were really consistent.

I had a set of narrow pad rockers out of a 66'. They were all horrible, I had some intakes that were in the 1.36 range and the exhaust weren't any better. I've got a wide pad set that Tim Banning blueprinted for me on the motor and they are all very close.

I kept going and finally found some that are different.
Found a few 1.53s and one 1.5475.

So I'm beginning to see sometimes the target is missed....Im probably lucky these aren't horribly bad,
And the error is mostly in my favor.

Although tedious, there's no other way to know.....

Maybe I'll keep going and cherry pick the highest ratio of the bunch.

If the Indy rockers had more clearance to the tube in the head (Victor), this wouldn't be needed....

The only way to know what you get is to test all of the ones you have

I rounded up another set of MP, a set of stock used wide pads, and a set of Indy.
There might be another set of MP coming my way in the future but this seems like enough
testing for now. I feel I know what I'm talking about with these parts I've checked.

The very worst one is a 1.49 wide pad, the very best one is a 1.56 MP.

There are enough in-between to make closely matched sets, which is the goal (beyond knowing what's what).

The Indy's are consistent at a little over their advertised ratio, but don't fit the Victor heads
Very well. I decided I'm going to run Indy roller intake and MP exhaust on this 572.

When you are ready to put the big boy pants on.......

Nice stuff, but I will probably never go that way unless there's a very substantial discount involved.

Chuck did give me the opportunity to have a close-up look at those + a really good quote, but the rest of the vehicle needs attention more.

I've seen the good Big Boy heads, they ain't from Eddy
Take a look at the BAE # 8 heads with the really good rocker arm girdle and rocker arms
I wish that I could afford to use them, but I can't
The Eddy Victors are way better than stock stuff though

I was referring to the valve train - Cab! Billet BAE #8 heads and valve train are great if you are running top alcohol - If you are running naturally aspirated the best heads out there today are from Goodwin Competition

Aren't all the Goodwin hemi motors made on their own blocks with a different bore spacing than the stock Mopar 426 blocks?
As far as a all out race motor, N/A or power adder, I think you need to have a billet block these days to make them live at the power levels guys are making now
I don't like aluminum blocks for N/A, let alone billet blocks
But sometimes you need to use what works the best if you want to compete heads up against the rest of the racers

Thanks for taking the time to measure these & post the results for us.

I'm really glad somebody appreciates it, thanks for saying so.

I consider myself very fortunate to have been given a guided tour of T&D products already, by the professional who made all the decisions on
Double's engine. High level knowledge and the time taken to show me a thing or two will be remembered for a long, long time.

Other stuff is easily dismissed

So the question I need to ask, did you make any attempt to figure out what is different between the rockers with the highest versus lowest ratio.

Take a measurement from the adjustment ball to the bushing wall.
Take a measurement from the bushing to the contact portion of the pad?

I didn't attempt to perform those sort of measurements with any level of precision, because I feel I lack the expertise to make any changes to that area.

Knowing that others do have the expertise to change or correct that, though, I'd be greatful to learn how that is done (even if I never try it personally).

I did look reasonably close at pushrod-to-tube clearance, since that was the main driver to the whole exercise, and since all were checked
on the same two lifter bores/same head arrangement. It seemed to me pushrod clearance (or the lack therof) was fairly consistent in each group or type of rocker,
which led me down the path of believing in the possibility the pushrod
side could be the better of the two. The thought was, maybe the valve side of the rocker, maybe even the exact curvature of the pad, might the more inconsistent or
"difficult to get right" area. (?)

These are just gut feelings that developed right after the "Actually, I can't do anything about that" thought crept in, and I decided not to pursue the exact reasons why each one
arrived at a different ratio.