I posted on here last fall regarding a valve train instability issue that Dwayne Porter deduced was the result of valve float due to too low of spring pressure resulting from incorrect valve spring height and possibly bad valve springs while running a hydraulic roller cam.

It almost cost me a motor, but I caught the carnage beginning when I did a routine inspection and pulled the valve cover. I had blown the needle bearing cages out of all the exhaust rocker arms, bent several pushrods slightly and could see the cage material laying in my heads. I feel I was really lucky, as the car had just taken a first place in our annual Mopar Alley car show, and I had blipped it up to about 140 mph(on the track) on my way home. It was still running great, so I thought.

Under Dwayne's review of the cause of the issue, he found that this problem was already apparent on the initial dyno pull sheets, as indicated by the sudden drop in power at 5400 rpm. The motor was making 684 hp just before that drop.

I had Dwayne go completely through the heads and replace ALL the hardware and set them up for use with a solid roller. I went with the Isky red Zone bushed lifters for my street engine. Dwayne is a great man to do business with, and a true visionary in his field.

While the heads were off, Dwayne helped me spec out some custom Ross replacement pistons to reduce my compression enough to switch from race gas to pump gas. The compression drop was from 12.2 to 1 down to 10.2 to 1. The pistons came in around 514 grams. This motor has a very low reciprocating weight, and should love to rev, so I wanted to make sure I never had valve train instability problems again. I used top shelf components and took the extra step of correcting the rocker arm geometry.

I had my 1.6 to 1 T&D roller rockers rebuilt at T&D and put them on the heads. The geometry seemed way off with the roller tip reaching well above the centerline of the rocker shaft and the adjuster screw at a pretty step angle in relation to the pushrods. I still have the rebuilt set if anyone wants a deal on them.

I contacted Mike at B3 Racing and followed his instructions to get the measurements he needed to make a correction kit. As it turns out he was working on a similar project at his shop. He said in my case the geometry was so far off from ideal, that I would need to have custom rockers made by T&D. He figured out all the measurements and I had my parts a few weeks later. Mike is another great guy to do business with, and I highly recommend both men if you are locking for this type of work.

I know a lot of people on here are skeptical of this type of geometry correction, but the results speak for themselves. All you have to do to see if correcting your rocker arm geometry is worthwhile, is to look at my before and after pictures. It's such a dramatic difference, in my mind a guy would be crazy not to make this correction.

I consulted with Manton Pushrods shop foreman and upsized my pushrods to their 7/16" Stage 5 pushrods. Here is another business that provides exceptional customer service. Dwayne had increased the pushrod clearance on my heads when he had them apart and the thicker pushrods have plenty of clearance now.

I'll let the pictures of Mike's geometry correction solution do the rest of the talking on the subject of, "Is it worth taking this extra step".

https://en.m.wikipedia.org/wiki/Desmodromic_valve

Desmodromic valve control 1896. Interesting read. There is not much that has not been around for decades or even centuries.