273 adjustable rocker conundrum..

Bewy said

Almost positive the thread 'interference' in the original design was in the adjuster, not the rocker. The adjuster was hollow, & slightly oversize. When screwed into the rocker, the adjuster thread was able to 'compress' slightly because of the hollow centre. This kept the adjuster tight enough to stop it changing position. The thread in the rocker may well be a standard 3/8" NF thread, in which case adjusters with a locknut are probably available.

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I thought so to until............I actually did the mod and added the Crane adjusters to a set. The interference is in the rockers. With the Crane adjusters, you don't want the interference fit. The Crane adjusters were tight like the factory adjusters until I ran a 3/8-24 tap through all of them. Several times in fact. Loosened them right up. But I was like you. I thought it was in the adjusters too, but it's not.

Now......on the slant 6, it's different. The interference IS in the adjusters. I believe it's because the rockers are made only of folded sheet metal and are not strong enough to hold that interference fit for long. I was able to screw my Crane adjusters in my slant 6 rockers with my fingers. There's also enough room on the slant 6 rockers for the adjuster nut to fully seat without having to face the top of the rocker holes. I'll have pictures before much longer when I am able to get my camshaft in. Then I can assemble the head on the engine.