Early big block adjustable rocker arms

Just curious as to the quality and performance of the original early style adjustable rocker arms. Anyone use them or do any testing at the valve to see actual rocker arm ratios with them?

If your talking about the original ductile iron Mopar adjustable rocker arms found on the 300letter car motors and M.W. motors they do vary from 1.48 up to 1.53 ratio
if your talking about the early Isky ductile iron and other brand ductile iron adjustable they vary also
RAS use to bush and correct the ratio, even increase them up to 1.62 or so, but if your going to buy a use set and have them fixed why not buy a good new better set to start with like Comp Cams stainless bushed or some good aluminum roller rockers like T&D or Harland Sharp

Hey Cab, Yes, I was referring to the early 300/MW rockers. I just got a set with a 413 and was curious as to how disappointed I would be if I tried to use them with performance in mind. Wasn't sure if they were similar to the Crane or Isky adjustables overall and/or better than the stamp steel rockers for that matter. I'll measure them out at some point in comparison to the Cranes I have laying around, but given work and the holidays I was hopeful that maybe someone, I.E.(You) had good info on them already to tie me over until I got time to look into them myself. -Trent

I would check all of them at the valve retainers after knowing the lobe lift on all the lobes Tests, tests and test some more to learn

Run them. They are durable. Most I've tested are accurate. Contact Mike at B3 racing engines and have him hook you up with a geometry correction kit. That will eliminate 99.99% of any valve train issues you would be having.

Was just talking about this yesterday with a drag racing buddy...Not sure how fast you're going...I use them on my street car (11.04 @ 122.5) and our N/SS car (10.82 @ 124). No problems at all on track or the street. Both use solid roller cams.

Boy Mike has really disappeared hasn't he. I can't remember the last time he posted.

The production rockers on your engine are very durable.

We have used those rockers way back in the 60’s and 70’s before the advent of roller rockers and such.

Used many sets on many engines at .750” lift in Super Stock and never had a failure or concern.

Keep an eye on the rocker shaft bore though, that’s usually the first indicator of a poor oil system - scored rocker bores.

Excellent rocker arms for the street as long as they are in good condition. The bores get trashed if the oil isn't kept clean. If the bores are trashed you can get them bronze bushed.

Last week John But, you're right, I haven't been posting much but I do check in fairly often. I just don't have much time to get into any deep discussions of late.

Thanks for the info guys. I'll take a good look at them when I get them off the shafts and report back with my findings when I measure them out. Hopefully they will all be good to go. Thanks Again! -Trent